Patent Description:
In recent years, for the purpose of reducing fuel consumption of a vehicle, such as an automobile, further weight reduction of the vehicle has been required. To reduce the weight of a vehicle, not only the weight of a large part, such as a body forming the vehicle, but also the weights of various members, such as a lighting appliance including a headlight or the like, a speaker unit for automotive application as one component of an audio system to be loaded on the vehicle, a connection box and a connector for an automobile, and a guide pulley for a belt that drives engine accessories or the like of an automobile, need to be reduced.

The lighting appliance for a vehicle is generally provided with a lamp body including an opening, a front cover that covers the opening, an extension, a reflection mirror (reflector), a light source, electrical components, and the like. To reduce the weight of the lighting appliance for a vehicle, it is effective to form the lamp body with a resin material, the lamp body having a relatively high ratio of the weight to the total weight of the lighting appliance for a vehicle among the components of the lighting appliance for a vehicle.

In addition to further weight reduction, improvements in strength characteristics against vibration and in acoustic characteristics as a speaker unit are also required in the speaker unit for automotive application. To meet such requirements, it is desirable to form, for example, a case body (enclosure or cabinet), a frame, and the like of the speaker unit with a suitable compounded material.

The connection box and connector for an automobile is generally produced by performing injection molding using a glass fiber-reinforced thermoplastic resin composition in which a glass fiber is dispersed as a reinforcing material. The use of such a highly strong resin enables thinning and weight reduction of the connection box and the connector. On the other hand, when the connection box, the connector, and the like are produced by injection molding, runner end materials and mis-shot products are produced. In addition, connection boxes, connectors, and the like formed using a glass fiber-reinforced thermoplastic resin are collected from scrapped cars in some cases. However, deterioration in strength of a recycled glass fiber-reinforced thermoplastic resin due to recycling is significant. Therefore, when a recycled glass fiber-reinforced thermoplastic resin is used, thinning and weight reduction of a connection box, a connector, and the like are difficult from the viewpoint of retaining the strength. Thus, a fiber-reinforced material such that effects of thinning and weight reduction are not lost even if it is recycled, the fiber-reinforced material being excellent in recyclability, is desired.

In a pulley for a vehicle, a resin part is in general integrally molded along the outer periphery of a rolling bearing, and the resin part is formed by injection molding using a resin or the like containing a reinforced fiber from the viewpoint of productivity. However, in the case of the injection molding, a gate for adjusting the inlet velocity of a resin material is essential for an injection molding machine. In addition, at a part where the resin materials having flown from the gate into a metal mold join, a weld is produced to generate nonuniformity of the reinforced fiber in a circumferential direction, so that there is a possibility that unevenness in strength and size accuracy occurs. Therefore, when a pulley is produced by injection molding, the size accuracy of the outer peripheral portion, which guides a belt, in the resin part, the strength characteristics and the like to endure the tension of the belt are required. Being excellent in size accuracy is also required similarly in the lamp body.

Such weight reduction and improvements in strength characteristics of various molded members are also required in, for example, molded members, for a house for agriculture, not limited to members for a vehicle, such as an automobile. The house for agriculture is widely used for the purpose of protecting products in the house from the outside and retaining a constant environment. A transparent film using as the main raw material vinyl chloride, polyethylene, a polyethylene-vinyl acetate copolymer, polyethylene terephthalate (PET), a polyethylene-tetrafluoroethylene copolymer, or the like is mainly used as a film for a house for agriculture so that situation of the inside can be grasped to a certain extent from the outside. Further, in recent years, the scale of an agricultural house has been made large in some cases from the viewpoint such as improving productivity. In a large-scale house for agriculture, the weight of the film to be used for the house increases, making an influence on the skeleton that supports the whole house large. In addition, an area where a flying object from the outside contacts increases. Therefore, weight reduction, high modulus of elasticity, and high strength are required in a film for a house. Further, the recyclability of a material is also required in some cases from the viewpoint of efficient utilization of resources in recent years.

To meet the requirements as described above, cellulose fiber is regarded as promising as a compounding material for the resin part which various members are provided with. The cellulose fiber has excellent characteristics, such as a light weight, a high strength, a high modulus of elasticity, and a low linear thermal expansion, and therefore is widely known as a reinforcement material for a resin or the like. In addition, cellulose exists on the earth in a large amount and is a renewable natural resource, and therefore cellulose is suitable as a material having a high recyclability. Further, a micronized cellulose fiber has a more satisfactory surface smoothness as compared to a glass fiber and a carbon fiber. However, the cellulose fiber has a very high hydrophilicity and therefore has a poor affinity to a highly hydrophobic resin, such as polypropylene or polyethylene, so that the cellulose cannot be mixed uniformly with such a resin by only performing kneading mechanically with a twin-screw extruder or the like. Therefore, the mechanical properties of a resultant composite material have not necessarily been satisfiable and have been insufficient. Generally, in the case where a highly hydrophilic thermoplastic resin, such as polyethylene or polypropylene, is used when a molded material containing a cellulose fiber is produced, the dispersibility of the cellulose fiber is poor, making it very difficult to obtain further mechanical strength.

To solve such a problem, a technique of using a compatibilizer for the purpose of changing the dispersibility of cellulose in a resin for the better is known. In addition, attempts to improve the dispersibility of cellulose in a resin by subjecting the cellulose or the resin to a modification treatment with a modifier or the like are made (For example, see Patent Literatures <NUM> to <NUM> and Non-Patent Literature <NUM>).

For example, in Patent Literatures <NUM> and <NUM>, using an unsaturated dicarboxylic acid and/or an anhydride thereof as a compatibilizer or an interface reinforcement agent in a resin composition containing a cellulose-based material and a polyolefin is proposed. In Patent Literature <NUM>, using a polybasic acid anhydride as a hydrophobically modifying agent in part of hydroxy groups of microfibrillated cellulose to use a resultant hydrophobically modified cellulose fiber as a reinforcement material for a resin is proposed. In Patent Literature <NUM>, improving the dispersibility of cellulose by using polyethylene obtained by grafting a monomer having a carboxy group, which has affinity to a hydroxy group existing in cellulose, through a particular method is proposed.

In Patent Literature <NUM> a molded article is obtained by mixing polypropylene, an unsaturated carboxylic acid-modified polyolefin resin, dicumyl peroxide and wood flour.

In Non-Patent Literature <NUM> a composite is obtained by mixing kraft pulp (NBKP), polypropylene and maleic anhydride polypropylene.

Even though any of the above-described methods is used, the mechanical strength of a molded article is improved due to the reinforcement effect of cellulose, but further improvements in the mechanical strength are desired.

It is an object of the present invention to provide a molded article provided with a resin part formed with a thermoplastic resin composition capable of dispersing cellulose simply and uniformly in a highly hydrophobic resin and capable of improving the mechanical strength of a molded material formed using a resultant resin composition. It is also an object of the present invention to provide a molded article provided with a resin part formed with a cellulose-reinforced thermoplastic resin composition obtained using the thermoplastic resin composition.

The present inventors have conducted diligent studies for the purpose of solving the above-described problems to obtain findings that by allowing a resin composition to contain a cellulose fiber, a thermoplastic resin, and an organic peroxide, a thermoplastic resin composition having an improved dispersibility of the cellulose fiber is obtained and that by heating and kneading the thermoplastic resin composition to react the contained components, a cellulose-reinforced thermoplastic resin composition is obtained. The present inventors have found that as a result, the mechanical strength of molded materials formed using the thermoplastic resin composition and the cellulose-reinforced thermoplastic resin composition can remarkably be improved, and thereby a molded article provided with a resin part formed using the thermoplastic resin composition and a molded article provided with a resin part formed using the cellulose-reinforced thermoplastic resin composition are obtained.

The gist and constitution of the present invention are as follows.

In the present invention, a thermoplastic resin composition in which cellulose is uniformly dispersed and contained and a cellulose-reinforced thermoplastic resin composition obtained by heating and kneading the thermoplastic resin composition are used, thereby enabling providing a molded article provided with a resin part having an improved mechanical strength. In addition, the resin part of the present invention is formed with a cellulose-reinforced thermoplastic resin composition formed with a thermoplastic resin and a cellulose reinforcing agent. Therefore, realizing molded articles selected from a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley provided with a resin part, which are reduced in weight and highly strengthened and are excellent in recyclability and surface smoothness is enabled.

A molded article according to the present invention, wherein the molded article is a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley, is provided with a resin part formed with a thermoplastic resin composition, the thermoplastic resin composition containing <NUM> to <NUM> parts by mass of cellulose based on <NUM> parts by mass of a thermoplastic resin and containing an organic peroxide, wherein a tensile strength of a resin molded body formed with the thermoplastic resin composition measured in accordance with JIS K <NUM> is <NUM> MPa or more.

A cellulose-reinforced thermoplastic resin composition to be used in the present invention is obtained by heating and kneading the thermoplastic resin composition to react contained components. Therefore, a molded article according to the present invention, wherein the molded article is a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley, is provided with resin part formed with a cellulose-reinforced thermoplastic resin composition containing an ester-bonded composite resin (composite) of a hydroxy group of cellulose and a polyolefin resin having a carboxy group and a crosslinked structure, wherein a content of a cellulose component in the ester-bonded composite resin is <NUM> to <NUM>% by mass, and a tensile strength of a resin molded body formed with the cellulose-reinforced thermoplastic resin composition measured in accordance with JIS K <NUM> is <NUM> MPa or more;.

The tensile strength of the resin molded body formed with the thermoplastic resin composition to be used in the present invention is a characteristic or a physical property of the resin contained in this thermoplastic resin composition. Such tensile strength is evaluated in such a way that the cellulose-reinforced thermoplastic resin composition obtained by heating and kneading the thermoplastic resin composition to react the contained components is processed into a test specimen (resin molded body) having an embodiment which is in accordance with the test specimen Type <NUM> and conforms to the tensile strength evaluation in JIS K <NUM>. On the other hand, the contained components in the cellulose-reinforced thermoplastic resin composition have already reacted, and therefore the tensile strength can be evaluated only by processing the cellulose-reinforced thermoplastic resin composition into a test specimen (resin molded body) having an embodiment which is in accordance with the test specimen Type <NUM> and conforms to the tensile strength evaluation in JIS K <NUM>.

To react the contained components in the thermoplastic resin composition by use of the organic peroxide as a radical polymerization initiator, the temperature is equal to or higher than the temperature where the organic peroxide thermally decomposes and a radical reaction is initiated, specifically a one-minute half-life temperature of the organic peroxide or higher (preferably, a temperature that is higher than the one-minute half-life temperature by <NUM>). By heating and kneading the thermoplastic resin composition with a general twin-screw extruder, the cellulose-reinforced thermoplastic resin composition can be prepared as a pellet.

Hereinafter, the conditions of heating and kneading will be described, but these are not for specifying the method for producing the cellulose-reinforced thermoplastic resin composition to be used in the present invention, but are conditions for measuring the tensile strength which is a parameter as a physical property or a characteristic.

The temperature of kneading the thermoplastic resin composition is a temperature where the organic peroxide existing in the composition decomposes or higher, and is preferably a temperature that is higher than the one-minute half-life temperature of the organic peroxide to be used by <NUM>. It is to be noted that stirring is not particularly limited, and may be sufficient when performed, for example, at a rotational speed of <NUM> rpm with a screw diameter of <NUM> and L/D = <NUM>. This heating-and-kneading may be performed with a heating and kneading machine as a model instead of a heating and kneading machine for use in production.

When heating-and-kneading is performed with a twin-screw extruder [for example, KZW15TW-<NUM>-NH manufactured by TECHNOVEL CORPORATION], the heating-and-kneading is performed at a screw rotational speed of <NUM> rpm loading the thermoplastic resin composition into a hopper of the twin-screw extruder having a screw diameter of <NUM> and L/D = <NUM> with a feeder controlling each component by the mass to be supplied per hour and setting a barrel temperature in a kneading zone to a temperature higher than the one-minute half-life temperature of the organic peroxide by <NUM>.

A test specimen for a tensile test in accordance with the test specimen Type <NUM> in JIS K <NUM> is prepared from the cellulose-reinforced thermoplastic resin composition obtained by heating and kneading the thermoplastic resin composition to react the contained components, and the tensile strength is determined by measurement in accordance with JIS K <NUM> for this test specimen for a tensile test.

It is to be noted that when heating-and-kneading is performed with a twin-screw extruder, the test specimen is prepared with an injection molding machine [for example, ROBOTSHOT α-30C manufactured by FANUC CORPORATION] after drying a pellet of the thermoplastic resin composition at <NUM> for <NUM> hours, the pellet obtained by performing the heating-and-kneading with the twin-screw extruder. The tensile strength is measured with a tensile tester [for example, Instron tester <NUM> manufactured by Instron] under conditions of a distance between marked lines of <NUM> and a testing speed: <NUM>/min.

The tensile strength is preferable when it is higher, and is <NUM> MPa or more in the present invention, and the tensile strength is more preferably <NUM> MPa or more, still more preferably <NUM> MPa or more, and particularly preferably <NUM> MPa or more. It is to be noted that the upper limit of the tensile strength is realistically <NUM> MPa.

The tensile strength can be adjusted by the types and contents of the components contained in each of the above-described resin composition and cellulose-reinforced thermoplastic resin, and in particular, it is effective to adjust the amount of the organic peroxide to be compounded. For example, the tensile strength can be adjusted further effectively by using the amount of the organic peroxide to be compounded and the amount of a maleic anhydride-modified polyolefin to be compounded together in a well-balanced manner.

Hereinafter, description will be given from the thermoplastic resin composition in order.

The thermoplastic resin composition to be used for forming the resin part which the molded article of the present invention is provided with contains at least a thermoplastic resin, cellulose, and an organic peroxide. The thermoplastic resin composition contains a polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, and a polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof, which is a polyethylene resin selected from an ethylene homopolymer and an ethylene-α-olefin copolymer, wherein the α-olefin is <NUM>-butene, <NUM>-pentene, <NUM>-hexene or <NUM>-octene.

In the present invention, one of the thermoplastic resins is a polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof.

A base resin refers to a resin component the content of which is largest among the thermoplastic resins other than the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, the thermoplastic resins contained in the thermoplastic resin composition, and may be contained at least in the same mass as the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof. In addition, cellulose is not included in the thermoplastic resin.

The base resin to be used in the present invention is polyethylene resin.

The polyethylene is selected from an ethylene homopolymer and an ethylene-α-olefin copolymer, wherein the α-olefin is <NUM>-butene, <NUM>-pentene, <NUM>-hexene, and <NUM>-octene.

Examples of the ethylene-α-olefin copolymer include an ethylene-<NUM>-butene copolymer, an ethylene-<NUM>-pentene copolymer, an ethylene-<NUM>-hexene copolymer, and an ethylene-<NUM>-octene copolymer.

When the polyethylene resin is classified according to the density or the shape, polyethylene may be any of high density polyethylene (HDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and ultra high molecular weight-polyethylene (UHMW-PE).

The thermoplastic resin forming the cellulose-reinforced thermoplastic resin composition to be used for forming the resin part which the molded article of the present invention is provided with be a crosslinkable polyethylene resin. Examples of the crosslinkable polyolefin resin include low density polyethylene, middle density polyethylene, high density polyethylene, linear low density polyethylene, linear very low density polyethylene.

The polyolefin resin which is the base resin may be used singly, or two or more of the polyolefin resins each of which is the base resin may be used in combination. It is to be noted that when a plurality of polyolefin resins are used, the amounts of the other components to be compounded are specified assuming the total amount of the polyolefin resins to be <NUM> parts by mass of the polyolefin resins, unless otherwise noted.

The melt flow rate (MFR) of the polyolefin resin is usually <NUM> to <NUM>/<NUM> and, from the viewpoint of enhancing mechanical strength and production stability, the melt flow rate of the polyolefin resin is preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>, and still more preferably <NUM> to <NUM>/<NUM>. It is to be noted that in the present invention, the melt flow rate of the polyolefin resin, including the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, refers to the mass (g/<NUM>) of a polymer that flows out per <NUM> minutes at <NUM> under a load of <NUM> in accordance with JIS K <NUM>.

With respect to polyethylene, which is used as base resin, being formed from only carbon atoms and hydrogen atoms, the hydrophobicity is extremely high. On the other hand, the surface of cellulose fiber is a surface which has a hydroxy group and has a high polarity, and therefore has a low compatibility with a highly hydrophobic polyethylene resin, so that it is difficult to disperse the cellulose fiber uniformly. In the present invention, it is then used a polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof in order to uniformly disperse a highly hydrophilic cellulose fiber, which has a hydroxy group which is a polar group, in the highly hydrophobic polyethylene resin.

The carboxy group (-CO<NUM>H) existing in the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the - C(=O)-O-C(=O)- bond based on the acid anhydride have a high affinity to and compatibility with the hydroxy group (-OH) on the surface of the cellulose fiber due to interactions, such as a hydrogen bond and a dipole interaction. On the other hand, the polyolefin part of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof as well as a hydrophobic polyethylene resin has a high hydrophobicity and the structures thereof are similar, so that the polyolefin part has a high compatibility with and affinity to the hydrophobic polyethylene resin. Therefore, dispersing the cellulose fiber uniformly in the polyethylene resin is facilitated.

The polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof has a partial structure of interacting with the hydrophobic thermoplastic resin and a partial structure of interacting with hydrophilic cellulose in a molecule thereof, as described above, thereby functioning as a mediator to bind the hydrophobic thermoplastic resin and the hydrophilic cellulose together, and therefore is classified as a coupling agent.

In addition, the structural part of an unsaturated carboxylic acid or the anhydride thereof in the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof exists at an extremely near distance from the hydroxy group on the surface of the cellulose fiber, as described above. Therefore, an esterification reaction with the hydroxy group of the cellulose occurs easily and efficiently, and thereby a composite resin in which the cellulose and the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof are chemically bonded is formed.

In the present invention, a crosslinking reaction progresses between the base resin and cellulose of the cellulose fiber due to a radical obtained by decomposition of the organic peroxide, so that a firm composite resin is formed. Further, when the thermoplastic resin contains the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, the organic peroxide allows a crosslinked structure, which is formed due to the radical reaction between the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the base resin, to be formed. Thereby, the cellulose, the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, and the base resin are chemically bonded (covalently bonded) to each other and a firmer composite resin is formed.

The unsaturated carboxylic acid or the anhydride of thereof, which graft-modifies a polyolefin resin, in the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof may be a chain compound or a cyclic compound, but is preferably a cyclic compound, more preferably a cyclic unsaturated carboxylic anhydride.

With respect to the amount of graft modification with the unsaturated carboxylic acid or the anhydride thereof, <NUM> to <NUM> parts by mass of the unsaturated carboxylic acid or the anhydride thereof based on <NUM> parts by mass of the unmodified polyolefin resin is preferable, more preferably <NUM> to <NUM> parts by mass, and still more preferably <NUM> to <NUM> parts by mass.

Examples of the unsaturated carboxylic acid include maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid.

Examples of a cyclic acid anhydride among the unsaturated carboxylic anhydrides include acid anhydrides having a maleic acid skeleton, such as maleic anhydride, citraconic anhydride (methylmaleic anhydride), <NUM>,<NUM>-dimethylmaleic anhydride, <NUM>-(<NUM>-carboxyethyl)-<NUM>-methylmaleic anhydride, <NUM>-cyclohexene-<NUM>,<NUM>-dicarboxylic anhydride, phenylmaleic anhydride, <NUM>,<NUM>-diphenylmaleic anhydride, <NUM>,<NUM>-dihydro-<NUM>,<NUM>-dithiin-<NUM>,<NUM>-dicarboxylic anhydride, and <NUM>,<NUM>-bis(<NUM>,<NUM>,<NUM>-trimethyl-<NUM>-thienyl)maleic anhydride, and acid anhydrides having a phthalic acid skeleton, such as <NUM>-ethynylphthalic anhydride, <NUM>,<NUM>'-(ethin-<NUM>,<NUM>-diyl)diphthalic anhydride, <NUM>-(<NUM>-propynyl)phthalic anhydride, and <NUM>-phenylethynylphthalic anhydride.

Examples of a chain acid anhydride among the unsaturated carboxylic anhydrides include an acid anhydride of fumaric acid, itaconic acid, acrylic acid, or methacrylic acid, and mixed acid anhydrides of these unsaturated carboxylic acids with a saturated aliphatic carboxylic acid, an aromatic carboxylic acid, or a heterocyclic carboxylic acid.

It is preferable that the unsaturated carboxylic anhydride be a cyclic unsaturated carboxylic anhydride, more preferably an acid anhydride having a maleic acid skeleton, and particularly preferably maleic anhydride.

It is preferable that thermoplastic resin composition to be used in the present invention containing the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof be a maleic anhydride-modified polyolefin resin.

The polyolefin of the maleic anhydride-modified polyolefin is not particularly limited as long as the compatibility with the base resin is good. It is preferable that the maleic anhydride-modified polyolefin be maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, or maleic anhydride-modified polystyrene, and the maleic anhydride-modified polyolefin is more preferably maleic anhydride-modified polyethylene or maleic anhydride-modified polypropylene. It is to be noted that a maleic anhydride-modified copolymer of a copolymer of two selected from ethylene, propylene, and styrene is also preferable.

Examples of the maleic anhydride-modified polyethylene and the maleic anhydride-modified polypropylene include an ethylene-propylene copolymer modified with maleic anhydride, ethylene-α-olefin copolymers (such as an ethylene-vinyl acetate copolymer, an ethylene-hexene copolymer, and an ethylene-octene copolymer) modified with maleic anhydride, and styrene/ethylene/butylene/styrene (SEBS) having a group containing maleic anhydride. In addition, the maleic anhydride-modified polyethylene and the maleic anhydride-modified polypropylene may contain not only maleic anhydride but also a polar group (an alkylene glycol-based or (meth)acrylic acid-based monomer component) as a polar group to be grafted or copolymerized. Among these, particularly preferred maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene are maleic anhydride-modified polyolefins (polyethylene, polypropylene, polystyrene, or copolymers thereof), an ethylene-propylene copolymer modified with maleic anhydride, ethylene-α-olefin copolymers (such as an ethylene-vinyl acetate copolymer, an ethylene-hexene copolymer, and an ethylene-octene copolymer) modified with maleic anhydride, and styrene/ethylene/butylene/styrene (SEBS) having a group containing maleic anhydride.

It is most preferable that the maleic anhydride-modified polyolefin resin be a maleic anhydride-modified polyethylene. In particular, a maleic anhydride-modified polyethylene having a melt flow rate (MFR) at <NUM> under a load of <NUM> of <NUM> to <NUM>/<NUM> is preferable. In addition, a maleic anhydride-modified polyethylene having a relative intensity ratio in an infrared absorption spectrum of <NUM> to <NUM>, the relative intensity ratio measured in the infrared absorption spectrum, is preferable.

With respect to the relative intensity ratio in the infrared absorption spectrum, the maleic anhydride-modified polyethylene is hot-pressed at <NUM> and <NUM> kgf/cm<NUM> for <NUM> minutes to prepare a film having a thickness of <NUM>, and the infrared absorption spectrum of this film is measured. The relative intensity ratio in the infrared absorption spectrum can be measured by determining the relative intensity ratio of the maleic anhydride-modified polyethylene from a ratio of absorption intensity at around <NUM>-<NUM> (an absorption peak of C=O stretching vibration of a saturated <NUM>-memberd ring acid anhydride derived from maleic anhydride)/absorption intensity at around <NUM>-<NUM> (an absorption peak of rocking vibration of a methylene group derived from polyethylene).

When the relative intensity ratio in the infrared absorption spectrum is <NUM> to <NUM>, the thermoplastic resin can thereby be allowed to tightly adhere to the cellulose firmly at the interface between the two. The relative intensity ratio in the infrared absorption spectrum is more preferably <NUM> to <NUM>.

With respect to the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, it is preferable that a polyolefin resin before modification and a polyolefin base resin not modified with an unsaturated carboxylic acid or an anhydride thereof be different polyolefin resins. Being different herein includes a difference in the types of resin components and in the constituent monomer components, and a difference in a physical property such as the MFR. In addition, the thermoplastic resin to be used in the present invention may be a mixed resin of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof.

It is preferable that the content of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof be <NUM> to <NUM> parts by mass, more preferably <NUM> to <NUM> parts by mass, and still more preferably <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the base resin. When the content of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof is too small, a tight adhesion effect at the interface of the cellulose and the resin is not obtained sufficiently, so that an effect of improving the mechanical strength of the resin composition is not obtained sufficiently. On the other hand, when the content of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof is too large, the content gives a bad influence on the strength of the base resin, so that the strength of the whole resin composition is lowered.

The organic peroxide is a polymerization initiator that crosslinks polymer molecules of the thermoplastic resins, such as the base resin and the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, by a radical reaction. The organic peroxide is a compound having at least carbon atoms and an -O-O- bond, and examples thereof include a ketone peroxide, a peroxyketal, a hydroperoxide, a dialkyl peroxide, an acyl peroxide, an alkyl peroxyester, a diacyl peroxide, a monoperoxycarbonate, and a peroxydicarbonate. Among these, in the present invention, at least one organic peroxide selected from a peroxyketal, a dialkyl peroxide, a diacyl peroxide, an alkyl peroxyester, and a monoperoxycarbonate is preferable, and a dialkyl peroxide in particular is preferable. When the organic peroxide is represented by a formula, the organic peroxides represented by the following formulas (<NUM>) to (<NUM>) are preferable. <CHM>
<CHM>
<CHM>.

In the formulas, R<NUM> to R<NUM> each independently represent an alkyl group, a cycloalkyl group, or an aryl group. R<NUM> and R<NUM>, and R<NUM> and R<NUM> herein are optionally bonded to each other to form a ring. n represents an integer of <NUM> to <NUM>.

The alkyl group may be linear or branched. It is preferable that the carbon numbers of the alkyl group be <NUM> to <NUM>, more preferably <NUM> to <NUM>. It is preferable that the number of ring members of the cycloalkyl group be <NUM> to <NUM>, more preferably <NUM> or <NUM>. It is preferable that the carbon numbers of the cycloalkyl group be <NUM> to <NUM>, more preferably <NUM> to <NUM>. Examples of the cycloalkyl group include cyclopropyl, cyclopentyl, and cyclohexyl.

The alkyl group and the cycloalkyl group optionally have a substituent, and examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an acyloxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a halogen atom, and a carboxy group.

It is preferable that the carbon numbers of the aryl group be <NUM> to <NUM>, more preferably <NUM> to <NUM>. The aryl group optionally has a substituent, and examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, and a halogen atom. Examples of the aryl group include phenyl and naphthyl, and phenyl is preferable.

It is preferable that the ring formed in such a way that R<NUM> and R<NUM> are bonded to each other be a <NUM>- or <NUM>-membered saturated carbon ring, and be a cyclopentane ring or a cyclohexane ring. It is preferable that the ring formed in such a way that R<NUM> and R<NUM> are bonded to each other be a <NUM>- to <NUM>-membered ring, and a bond forming the ring optionally contains -O-O-.

It is preferable that the organic peroxide represented by formula (<NUM>) also be a bis form as shown in the following formula (2a) in which R<NUM> and R<NUM> are bonded to each other to form a ring.

In the formula, R<NUM> and R<NUM> are as defined for R<NUM> and R<NUM> in formula (<NUM>), and preferred ranges thereof are also the same. L<NUM> represents a divalent linking group, and it is preferable that L<NUM> be -O-, -S-, -SO<NUM>-, -C(=O)-, an alkylene group, or an arylene group.

It is preferable that the organic peroxide represented by formula (<NUM>) also be a bis form as shown in the following formula (4a) when R<NUM> is an alkyl group having a substituent.

In the formula, R<NUM> is as defined for R<NUM> in formula (<NUM>), and preferred ranges thereof are also the same. R4a represents an alkylene group, a cycloalkylene group, or an arylene group, L<NUM> represents a divalent linking group, and it is preferable that L<NUM> be -O-, -S-, -SO<NUM>-, -C(=O)-, an alkylene group, an ethenylene group, an ethynylene group, or an arylene group.

Among the organic peroxides represented by formulas (<NUM>) to (<NUM>), the organic peroxides represented by formulas (<NUM>), (<NUM>), and (<NUM>) to (<NUM>) are preferable, and the organic peroxide represented by formula (<NUM>) in particular is preferable.

Examples of the organic peroxide include the following specific examples.

It is preferable that the one-minute half-life temperature of the organic peroxide be <NUM> to <NUM>. The half-life of the organic peroxide herein refers to a time until the amount of active oxygen in the organic peroxide becomes half the amount before decomposition when the organic peroxide decomposes due to heat. When the one-minute half-life temperature of the organic peroxide is too high, setting the temperature in a twin-screw extruder is made difficult, and conversely when the one-minute half-life temperature is too low, the organic peroxide itself is unstable and decomposes during storage. By setting the one-minute half-life temperature to the range as described above, heating-and-kneading is enabled with a twin-screw extruder which is used usually, enabling dispersing cellulose uniformly in a highly hydrophobic resin.

The one-minute half-life temperature of the organic peroxide is determined by preparing an organic peroxide solution having a concentration of <NUM> mol/L using a relatively inactive solvent, such as benzene, and measuring a change in the organic peroxide concentration with time when the organic peroxide is thermally decomposed (see "<NPL>).

It is preferable that the content of the organic peroxide be <NUM> to <NUM> parts by mass, more preferably <NUM> to <NUM> parts by mass, and still more preferably <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the thermoplastic resin. When the content of the organic peroxide is too small, an effect of improving the mechanical strength of the resin composition is not obtained sufficiently. On the other hand, when the content of the organic peroxide is too large, the thermal fluidity of the resin composition is lowered, making it difficult to perform processing by molding.

RO· (A radical) which is obtained by decomposition of the organic peroxide abstracts a hydrogen atom of the base resin and of the cellulose to produce radicals of the base resin and the cellulose further. It is inferred that the produced radical of the base resin and the produced radical of the cellulose undergo a bonding reaction and thereby the base resin and the cellulose adhere to each other at the interface thereof. The above-described tight adhesion reaction at the interface is as follows when a case where the base resin is polyethylene is taken as an example.

Herein, PE-H represents polyethylene, Cellulose-H represents cellulose, PE· and Cellulose·each represent a produced radical.

It is preferable that the cellulose to be used in the present invention be plant-derived fibrous cellulose, especially plant-derived, micro-fibrous cellulose. In the molded article provided with a resin part of the present invention, wherein the molded article is a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley, cellulose is used as a compounding material for the resin part, weight reduction and high strengthening can be achieved, and recyclability and surface smoothness of the molded article can be improved. According to a particular aspect, not according to the present invention, when the molded article is like a film, a film for a house, as a molded article, can possess an improved surface smoothness by including a layer of the thermoplastic resins in which such fibrous cellulose is composited, and a film for a house possessing an excellent light permeability can thereby be obtained. In addition, cellulose is a polar molecule having an -OH group, and the affinity between molecules is therefore high. Thus, a film for a house excellent in adhesion performance can be obtained because the interfacial adhesive force of the film for a house is improved. Thereby, an advantageous point, such as, for example, that the film for a house, when broken, can simply be repaired with an adhesive tape or the like, is obtained.

Pulp is a raw material for paper and contains as the main component a tracheid which is extracted from a plant. From the chemical viewpoint, the main component of pulp is a polysaccharide, and the main component of the polysaccharide is cellulose. The plant-derived fibrous cellulose is not particularly limited, and examples thereof include plant-derived cellulose such as wood, bamboo, hemp, jute, kenaf, harvest losses of farm products (for example, straw of wheat, rice, or the like, maize, stems of raw cotton or the like, sugarcane), cloth, regenerated pulp, and old paper; however, in the present invention, wood or wood-derived fibrous cellulose is preferable, and the plant-derived fibrous cellulose is particularly preferably craft pulp. It is to be noted that the craft pulp is a general term of pulp obtained by removing lignin/hemicellulose from wood or a plant raw material by a chemical treatment with caustic soda or the like to take out cellulose that is almost pure.

It is preferable that the diameter of the cellulose to be used in the present invention be <NUM> to <NUM>, more preferably <NUM> to <NUM>, and still more preferably <NUM> to <NUM>. In addition, it is preferable that the length (fiber length) be <NUM> to <NUM>, more preferably <NUM> to <NUM>.

In the present invention, the amount of the cellulose to be compounded is <NUM> to <NUM> parts by mass, more preferably <NUM> to <NUM> parts by mass, and still more preferably <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the thermoplastic resin. When the amount of the cellulose to be compounded is less than <NUM> parts by mass, a sufficient effect of reinforcement of a resin is not obtained, and conversely, when the amount of the cellulose to be compounded exceeds <NUM> parts by mass, the thermal fluidity of the resin composition is lowered, so that the molding processability is deteriorated, and the mechanical strength is lowered in some cases according to the circumstances.

To the thermoplastic resin composition to be used in the present invention, an inorganic filler, such as, for example, talc, calcium carbonate, mica, and a glass fiber, or an organic filler, such as, for example, a polyester, and a polyamide fiber, and besides, various additives, such as a flame retardant, a stabilizer, an antioxidizing agent, an infrared ray absorber, a plasticizer, and a lubricant, and a colorant, such as a dye and a pigment, can be added.

A component forming the thermoplastic resin composition to be used in the present invention can be compounded in an amount within a general range, except that <NUM> to <NUM> parts by mass of cellulose based on <NUM> parts by mass of the thermoplastic resin composition is contained, but it is most preferable that all the components be each compounded in an amount within a preferred range. However, the following remains unchanged: it is also a preferred aspect that a particular component is in a preferred range and the other components are each compounded in an amount within a general range.

The cellulose-reinforced thermoplastic resin composition to be used in the present invention is produced from the above-described thermoplastic resin composition. The cellulose-reinforced thermoplastic resin composition to be used in the present invention is such that by heating and kneading the above-described thermoplastic resin composition, the contained components have reacted. In the above-described reaction, the base resin and a hydrogen atom of the cellulose of the cellulose fiber react due to the organic peroxide which is a radical reaction initiator, so that a crosslinking reaction between the base resin and the cellulose fiber progresses. Further, when the thermoplastic resin contains a polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the cellulose react, so that an ester bond of a hydroxy group of the cellulose and the polyolefin resin having a carboxy group and a crosslinked structure is formed.

Accordingly, the cellulose-reinforced thermoplastic resin composition to be used in the present invention has a crosslinked structure between the thermoplastic resin and the cellulose of the cellulose fiber, and further, contains an ester-bonded composite resin (composite) of a hydroxy group of the cellulose and the polyolefin resin having a carboxy group and a crosslinked structure. Herein, the content of the cellulose component in the ester-bonded composite resin is <NUM> to <NUM>% by mass, and the tensile strength of a resin molded body formed with the cellulose-reinforced thermoplastic resin composition measured in accordance with JIS K <NUM> is <NUM> MPa or more. It is to be noted that the content of the cellulose component in the composite is calculated as the cellulose component based on the total content of the thermoplastic resin component and the cellulose component each contained, as a component forming the composite, in the thermoplastic resin composition for obtaining the cellulose-reinforced thermoplastic resin composition.

Besides what is described above, the crosslinking reaction that is caused by the organic peroxide which is a radical reaction initiator also forms a crosslinked structure in which a carbon atom of the main chain in the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and a carbon atom of the main chain in the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof are bonded at two or more sites.

Accordingly, the polyolefin resin having a carboxy group and a crosslinked structure be a polyolefin resin having a crosslinked structure in which a carbon atom of the main chain in the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and a carbon atom of the main chain in the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride, which is a polyethylene, are bonded at two or more sites. It is to be noted that when the thermoplastic resin composition contains a polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof, the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof is included in the components forming the composite.

On this occasion, the polyolefin resin before modification for obtaining the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof as well as those in the above-described thermoplastic resin composition may be different polyolefin resins.

In addition, it is preferable that the cellulose contained in the cellulose-reinforced thermoplastic resin composition as well as the cellulose contained in the above-described thermoplastic resin composition be plant-derived fibrous cellulose, especially plant-derived, micro-fibrous cellulose.

The cellulose-reinforced thermoplastic resin composition is produced by heating and kneading the thermoplastic resin composition as described above. The apparatus to be used in kneading-and-heating is not particularly limited as long as heating-and-kneading can be performed at a temperature where the organic peroxide thermally decomposes, and examples thereof include a blender, a kneader, a mixing roll, a Banbury mixer, and a single-screw or twin-screw extruder. Among these, a twin-screw extruder is preferable. The cellulose-reinforced thermoplastic resin composition can be obtained with a twin-screw extruder by directly loading each component into a hopper unit of the twin-screw extruder with a weight feeder, kneading loaded components with the twin-screw extruder setting the setting temperature of the kneading zone to the above-described temperature, and reacting this kneaded product while heating the kneaded product.

The cellulose-reinforced thermoplastic resin composition produced separately preparing the thermoplastic resin composition to be used in the present invention may be used, but it is preferable to produce the cellulose-reinforced thermoplastic resin composition in such a way that at a stage of producing the cellulose-reinforced thermoplastic resin composition with, for example, an extruder [for example, a twin-screw extruder such as KZW15TW-<NUM>-NH manufactured by TECHNOVEL CORPORATION], each component is loaded into a hopper of the extruder with a feeder controlling each component by the mass to be supplied into this extruder per hour, and a resultant thermoplastic resin composition is heated and kneaded. In such a method, existing apparatuses and facilities can be used without changing the facilities, and the cellulose-reinforced thermoplastic resin composition can be produced simultaneously with the preparation of the thermoplastic resin composition.

As described above, heating-and-kneading is performed by loading each component into the hopper of the extruder and setting a barrel temperature in the kneading zone to, for example, a temperature where the organic peroxide thermally decomposes. The kneading temperature is set to a temperature higher than the one-minute half-life temperature of the organic peroxide. It is preferable that the kneading temperature be a temperature higher than the one-minute half-life temperature of the organic peroxide by <NUM> or more, more preferably a temperature higher by <NUM> or more, still more preferably a temperature higher by <NUM> or more, and most preferably a temperature higher by <NUM> or more.

When a general organic peroxide is used, it is preferable that the kneading temperature be <NUM> to <NUM>.

With respect to heating-and-kneading, performing heating-and-kneading with, for example, a screw diameter of <NUM> and L/D = <NUM> at a screw rotational speed of <NUM> rpm is sufficient. The kneading time is not particularly limited, and may be a general reaction time when a usual organic peroxide is used.

When the cellulose-reinforced thermoplastic resin composition is produced using an extruder, the cellulose-reinforced thermoplastic resin composition can also be used for producing a molded article, such as a lamp body of a lighting appliance, a speaker unit, a connection box, a connector, a pulley, or a film for a house, the molded article being provided with a resin part by making the cellulose-reinforced thermoplastic resin composition into a pellet.

It is to be noted that in the cellulose-reinforced thermoplastic resin composition to be used in the present invention, an organic peroxide is compounded, therefore a decomposition residue of the organic peroxide is left in some cases by performing heating-and-kneading to perform reaction, and as a result, the decomposition residue may be contained in the cellulose-reinforced thermoplastic resin composition.

The resin part of the molded article according to the present invention is formed using the cellulose-reinforced thermoplastic resin composition obtained by heating and kneading the thermoplastic resin composition to be used in the present invention. That is, the resin part is formed from the cellulose-reinforced resin composition containing an ester-bonded composite resin (composite) of a hydroxy group of cellulose and a polyolefin resin having a carboxy group and a crosslinked structure, wherein the content of the cellulose component in the ester-bonded composite resin is <NUM> to <NUM>% by mass, and the tensile strength of a resin molded body formed with the cellulose-reinforced thermoplastic resin composition measured in accordance with JIS K <NUM> is <NUM> MPa or or more;.

In the molded body provided with a resin part according to the present invention, the tight adhesion at the interface between the thermoplastic resin and cellulose is changed for the better by the use of the cellulose-reinforced thermoplastic resin composition, as described above. Therefore, the resin part of an obtained molded article is excellent in mechanical strength, such as, for example, tensile strength. The molded article of the present invention is a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley.

<FIG> is a schematic sectional diagram showing an example of a lamp body of a lighting appliance according to an embodiment of the molded article. In <FIG>, a configuration of a headlight (headlamp) as a lighting appliance for a vehicle is shown as an example of a lighting appliance <NUM>. The lighting appliance <NUM> includes a lamp body <NUM>, a front cover <NUM>, a light source <NUM>, a reflection mirror (reflector) <NUM>, and a socket part <NUM>. The lamp body <NUM> includes an opening <NUM> at the front. The front cover <NUM> is attached to the lamp body <NUM> in such a way as to cover the opening <NUM> of the lamp body <NUM>. Thereby, a space <NUM> closed up tightly by the lamp body <NUM> and the front cover <NUM> is formed.

The light source <NUM> and the reflection mirror <NUM> are disposed in the space <NUM>. The light source <NUM> is, for example, a LED light bulb or a halogen light bulb. The light source <NUM> is connected to the socket part <NUM> fixed in a through hole <NUM> formed in the lamp body <NUM> and emits light by electric power supplied from the socket part <NUM>.

The reflection mirror <NUM> includes a concave surface <NUM> dented toward the front cover <NUM>. A hole is formed at the central part of the reflection mirror <NUM>, and the light source <NUM> is inserted and fixed in the hole. The reflection mirror <NUM> reflects the light emitted from the light source <NUM> by the concave surface <NUM> to lead the light on the side of the front cover <NUM>.

The front cover <NUM> is formed from a light (visible light)-transmittable resin material. The front cover <NUM> also functions as a lens that condenses or diffuses light from the light source <NUM>.

The lamp body <NUM> herein is provided with a resin part formed with the above-described thermoplastic resin composition. Thereby, weight reduction and high strengthening of the lamp body <NUM> can be achieved, and the recyclability and the surface smoothness can be improved.

The method of producing the lamp body <NUM> is not particularly limited, and the lamp body <NUM> can be molded by injection molding of injecting the thermoplastic resin composition into a metal mold. Thereby, the resistance against wear of a metal mold is improved, and a metal mold is made difficult to corrode.

<FIG> shows an example of a case where the whole of the lamp body <NUM> is formed by the resin part, but the lamp body <NUM> is not limited to this and may include the resin part and a part formed with a material other than a resin. In addition, <FIG> shows an example of a case where the lighting appliance <NUM> is a headlight; however, the lighting appliance <NUM> is not limited to this, and the lamp body <NUM> can be applied as a lamp body of a lighting appliance for a vehicle, such as a brake lamp, a fog lamp, and a reversing light. Further, the lamp body <NUM> can be applied as a body part (housing) of various lighting appliances, not limited to the lighting appliance for a vehicle.

<FIG> is a perspective diagram showing an example of a speaker unit according to an embodiment of the molded article. A speaker unit <NUM> is provided with: an almost tightly-closed case body (enclosure) <NUM> formed by a board-like baffle <NUM> and a box-like storing part <NUM> bonded to the back of the baffle <NUM>; and a speaker <NUM> held by the case body <NUM> in such a way as to expose a sound-emitting surface to the surface of the baffle <NUM>. It is to be noted that the case body (enclosure) <NUM> is also generally called a speaker box or a cabinet and has various shapes, such as a box type, a cylindrical type, and a conical type, depending on an apparatus or the like to which the case body <NUM> is applied. The speaker <NUM> includes: an exciter <NUM> as a source of vibration for a magnetic circuit; and cone paper <NUM> that releases a sound wave generated by the vibration of the exciter <NUM> outside the case body <NUM>.

<FIG> is a perspective diagram showing a speaker apparatus <NUM> for automotive application, which is an embodiment of applying the speaker unit to a speaker apparatus for automotive application. <FIG> is a sectional diagram of the speaker apparatus <NUM> for automotive application shown in <FIG>, the sectional diagram viewed from the arrow direction along the line A-A in <FIG>. As shown in <FIG> and <FIG>, the speaker unit <NUM> to be used as the speaker apparatus <NUM> for automotive application is provided between an outer panel <NUM> on the vehicle outer side and an inner panel <NUM> on the vehicle inner side, the panels forming a door in a vehicle, such as an automobile, and is attached in a state where the speaker unit <NUM> is exposed from the opening of the inner panel <NUM>. It is to be noted that to the inner panel <NUM>, an inner trim <NUM> covering the surface of the inner panel <NUM> is attached in a state of exposing the speaker unit <NUM>.

In the speaker unit <NUM> used for the speaker apparatus <NUM> for automotive application shown in <FIG>, the above-described thermoplastic resin composition is used for the baffle <NUM>, the storing part <NUM>, and the cone paper <NUM> of the case body <NUM>. Thereby, weight reduction and improvements in strength characteristics and acoustic characteristics can be achieved in the speaker apparatus <NUM> for automotive application. The speaker unit <NUM> in particular can contribute to reducing fuel consumption of a vehicle due to the weight reduction and is made highly strong, and therefore vibration of the case body <NUM> caused by vibration of a vehicle can be suppressed. As a result, noise attributable to the vibration of the case body <NUM> can be reduced and the acoustic characteristics can be improved. In addition, the above-described thermoplastic resin composition is used for the speaker unit <NUM>, and therefore the speaker unit <NUM> exhibits an excellent whitening resistance. Further, the speaker unit <NUM> includes the case body <NUM> formed with the thermoplastic resin composition and therefore is rich in recyclability and surface smoothness.

The object of applying the speaker unit is not limited to an automobile, and examples thereof include mobile objects such as a two-wheeled vehicle, a railroad vehicle, a plane, and a ship, a computer apparatus, a headphone, or all the speaker apparatuses to be installed for home-use.

<FIG> is a perspective diagram showing a connection box according to an embodiment of the molded article. <FIG> is a disassembled perspective diagram of the connection box shown in <FIG>. A connection box <NUM> is formed, for example, as a junction box to be installed on the indoor side of an automobile. This connection box <NUM> is provided with a case <NUM> including a first case 320a and a second case 320b.

The connection box <NUM> is provided with a first substrate 340a, a second substrate 340b, and a third substrate 340c in the accommodating space inside thereof. The first substrate 340a and the second substrate 340b are disposed in such a way as to be in parallel with each other, and the third substrate 340c is disposed in such a way as to be vertically connected to end portions of the first substrate 340a and the second substrate 340b.

On a mounting surface <NUM> of the first case 320a, an electronic control unit (ECU: Electronic Control Unit) not shown in the figures is to be installed. A connector <NUM> for ECU of the first substrate 340a is disposed in such a way as to protrude from the mounting surface <NUM> and can electrically connect the circuit of the first substrate 340a to ECU.

From the end portion of the second case 320b, a connector <NUM> for mounting a relay, the connector integrated with the case <NUM> of the connection box <NUM>, protrudes. A relay not shown in the figures can be mounted to the connector <NUM> for mounting a relay.

An indoor side connector 342a is disposed on the first substrate 340a, and an indoor side connector 342b is disposed on the second substrate 340b. These indoor side connectors 342a, 342b are each electrically connected to a circuit on the indoor side of an automobile through a wire harness not shown in the figures. A connector <NUM> for mounting a relay is disposed on the second substrate 340b. In the example shown in the figures, three relays can be loaded to the connector <NUM> for mounting a relay. An engine room side connector <NUM> is disposed on the third substrate 340c. This engine room side connector <NUM> is to be electrically connected to a circuit on the engine room side through a wire harness not shown in the figures.

In this way, the case <NUM> and connectors <NUM>, <NUM> to <NUM> of the connection box <NUM> are formed using the thermoplastic resin composition, and therefore weight reduction and high strengthening can be achieved, and recyclability and surface smoothness can be improved.

The method of producing the connection box and the connector is not particularly limited, and the connection box and the connector can be molded by injection molding of injecting the thermoplastic resin composition into a metal mold. It is to be noted that the connector in the present invention includes a connector housing, the connector itself, a connector integrated with a connection box case, and the like.

Examples of the uses of the connection box and the connector include a material for transportation equipment, such as an automobile, a two-wheeled vehicle, a train, and an airplane, a structural member of a robot arm, parts for a robot for amusement, a material for a home electric appliance, a case body for office automation equipment, information processing equipment, and a portable terminal.

<FIG> shows a front diagram of a pulley according to an embodiment of the molded article, and <FIG> shows a sectional diagram of <FIG>, the sectional diagram taken along the line B-B in <FIG>. As shown in <FIG>, a pulley <NUM> is formed by a rolling bearing <NUM> and a resin part <NUM> integrally molded around the rolling bearing <NUM>. The rolling bearing <NUM> includes an inner ring <NUM>, an outer ring <NUM>, and a rolling element <NUM> provided between the inner and outer rings. The resin part <NUM> is formed using the thermoplastic resin composition. The resin part <NUM> is provided with a cylindrical boss <NUM>, a cylindrical rim <NUM>, and an annular part <NUM> that connects the boss <NUM> and the rim <NUM>. The outer peripheral surface <NUM> of the rim <NUM> is a guide surface of a belt not shown in the figures.

<FIG> shows an example where the resin part <NUM> is formed using the thermoplastic resin composition, but the whole pulley may be formed using the thermoplastic resin composition. This can contribute to weight reduction and high strengthening of the pulley <NUM>. The method of producing the pulley <NUM> is not particularly limited, but the pulley <NUM> can be molded by injection molding of disposing the rolling bearing <NUM> in a metal mold and injecting the thermoplastic resin composition into the metal mold. Thereby, the resistance against wear of a metal mold and the smoothness of the edge (sharp-edge characteristic) of the resin part <NUM> can be improved. In addition, by performing injection molding using the thermoplastic resin composition, a pulley <NUM> which is reduced in weight and highly strengthened and is excellent in recyclability, surface smoothness, and further, size accuracy can be molded.

Examples of the use of the pulley include a material for transportation equipment, such as an automobile, a two-wheeled vehicle, a train, and an airplane, a structural member of a robot arm, parts for a robot for amusement, a material for a home electric appliance, a case body for office automation equipment, information processing equipment, and a portable terminal.

<FIG> is a schematic perspective diagram showing an example of an appearance of an agricultural house to which a film for a house according to an aspect of the molded article is applied. As shown in <FIG>, a house <NUM> for agriculture is provided with a film <NUM> stretched over a skeleton <NUM>.

As shown in <FIG>, the whole surface of the house <NUM> for agriculture is covered with the film <NUM> stretched over the skeleton <NUM>. When the film <NUM> is stretched over the skeleton, the house for agriculture in which a space separated from the outside is thereby formed can be made.

The material forming the skeleton <NUM> is not particularly limited, and a conventionally known aggregate (such as, for example, steel material and steel pipe) for use in a plastic greenhouse can be used. The film <NUM> is a film to be stretched over the skeleton <NUM>, and the above-described film for a house is applied to the film <NUM>.

The house <NUM> for agriculture may be provided with ventilation means (not shown in the figure), such as, for example, a ventilation fan, to be provided at the ceiling or the side of a house. In addition, it is preferable that the doorway (not shown in the figure) for a worker who is engaged in work in the house <NUM> for agriculture be, for example, double-entry doors or the like such that the air outside cannot directly get into the space in the house.

The film <NUM> in the house <NUM> for agriculture includes a layer which is formed using the thermoplastic resin composition. Thereby, the film <NUM> possesses recyclability together with weight reduction and high strengthening, and further, the surface smoothness and the adhesion performance can be improved more than a conventional film.

The film <NUM> (film for a house) may include a layer which is formed from the thermoplastic resin composition and can be produced by a known method, such as, for example, an inflation molding method, a T-die molding method, a lamination method, and a calender method.

The film <NUM> (film for a house) may be a single-layered or multi-layered film including one layer or a plurality of layers which is or are formed using the thermoplastic resin composition, or a laminated film in which on a layer formed from the thermoplastic resin composition, a resin layer formed from another resin composition is laminated. Examples of the resin capable of forming the other resin layer which can be laminated on the layer formed from the thermoplastic resin composition include a polyolefin resin which is usually used for a use as a film for a house.

The thickness of the layer which is formed from the thermoplastic resin composition, the layer included in the film <NUM> (film for a house) is, for example, <NUM> or more and <NUM> or less, the lower limit value is preferably <NUM> or less, and it is preferable that the upper limit value be <NUM> or less. When the film for a house is a multi-layered film, the thickness of the film for a house can appropriately be set according to the use or the like.

<FIG> shows an example of a case where the film <NUM> (film for a house) is applied to the whole surface of the house <NUM> for agriculture, but the house <NUM> for agriculture is not limited to this and may be such that the film for a house is used in some of the surfaces of the house <NUM> for agriculture. In addition, the house <NUM> for agriculture can be prepared in such a way that a framework is built in desired width, depth, and height, and the film <NUM> (film for a house) obtained using the above-described thermoplastic resin composition is stretched over the skeleton <NUM>. Thereby, a house <NUM> for agriculture which is reduced in weight and highly strengthened and is excellent in recyclability can be obtained.

Examples of the use of the film for a house include a house for gardening, a house for raising a living thing, a house for a terrace, and a simple warehouse, not limited to a house for agriculture, the house for cultivating plants.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples. The materials used are shown below.

Firstly, common production method, molding method, and physical property evaluation method, which are performed in Examples and Comparative Examples, will be described.

A thermoplastic resin composition, in which the above-described (<NUM>) thermoplastic resins (base resin and maleic anhydride-modified polyethylene), (<NUM>) cellulose, and (<NUM>) organic peroxide are each contained in a content shown in Table <NUM> to Table <NUM> below, was prepared. The obtained thermoplastic resin composition was loaded into a hopper of a twin-screw extruder [KZW15TW-<NUM>-NH manufactured by TECHNOVEL CORPORATION] having a screw diameter of <NUM> and L/D = <NUM> with a feeder controlling the obtained thermoplastic resin composition by the mass to be supplied per hour. The barrel temperature was set to a temperature higher than the one-minute half-life temperature of the organic peroxide by <NUM> to perform heating-and-kneading at a screw rotational speed of <NUM> rpm, thereby obtaining a cellulose-reinforced thermoplastic resin composition. It is to be noted that when the thermoplastic resin contained a maleic anhydride-modified polyethylene, the maleic anhydride-modified polyethylene used was described as a coupling agent in Tables <NUM> to <NUM> for convenience.

Injection molding was performed using the cellulose-reinforced thermoplastic resin composition prepared above to separately prepare a lamp body, a speaker unit, a connection box and a connector, and a pulley each provided with a resin part. It is to be noted that with respect to injection conditions, injection molding was carried out under the molding conditions which are generally regarded as suitable in injection molding of these molded articles.

A single-layered film having a thickness of <NUM> was prepared to obtain a film for a house by molding the cellulose-reinforced thermoplastic resin composition prepared above into a film using a T-die cast film production apparatus at an extruding temperature of <NUM>.

Pellets of the cellulose-reinforced thermoplastic resin compositions obtained above were dried at <NUM> for <NUM> hours to prepare respective test specimens for a tensile test in accordance with the test specimen Type <NUM> in JIS K <NUM> with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION].

The tensile strength (MPa) of the test specimens for a tensile test prepared above was measured in accordance with JIS K <NUM> with a tensile tester [Instron tester <NUM> manufactured by Instron] under conditions of a distance between marked lines of <NUM> and a testing speed: <NUM>/min.

The MFR of the base resin and the maleic anhydride-modified polyethylenes A to G, which are thermoplastic resins, the relative intensity ratio in the infrared absorption spectrum of the maleic anhydride-modified polyethylenes A to G, and the one-minute half-life temperature of the organic peroxides to be used were measured in the following manners.

The mass (g/<NUM>) of a polymer that flows out per <NUM> minutes at <NUM> under a load of <NUM> was determined using MELT INDEXER [manufactured by Toyo Seiki Seisaku-sho, Ltd. ] in accordance with JIS K <NUM>.

Each maleic anhydride-modified polyethylene was hot-pressed at <NUM> and <NUM> kgf/cm<NUM> for <NUM> minutes to prepare a film having a thickness of <NUM>. The infrared absorption spectrum of this film was measured to determine the relative intensity ratio from the ratio of absorption intensity at around <NUM>-<NUM>/absorption intensity at around <NUM>-<NUM>.

The half-life, which is a time until the amount of active oxygen in an organic peroxide becomes half the amount before decomposition when the organic peroxide decomposes due to heat, was determined by preparing a benzene solution of the organic peroxide the concentration of which is <NUM> mol/L and measuring a change in the organic peroxide concentration with time when the organic peroxide was thermally decomposed.

A thermoplastic resin composition formed using <NUM> parts by mass of the cellulose, <NUM> part by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the dialkyl peroxide A each based on <NUM> parts by mass of the high density polyethylene was heated and kneaded with a twin-screw extruder [KZW15TW-<NUM>-NH manufactured by TECHNOVEL CORPORATION] to obtain a pellet of a cellulose-reinforced thermoplastic resin. Thereafter, a test specimen for evaluating tensile strength was prepared using the pellet with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION].

Pellets of cellulose-reinforced thermoplastic resin compositions were each prepared in the same manner as in Example <NUM>, except that the compounded amount of the maleic anhydride-modified polyethylene A in the thermoplastic resin composition of Example <NUM> was changed as shown in Table <NUM> described below. Thereafter, test specimens as lamp bodies each provided with a resin part for evaluating tensile tension were each prepared using these pellets.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the dialkyl peroxide A each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the maleic anhydride-modified polyethylene A was not used in the thermoplastic resin composition of Example <NUM>. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the type of maleic anhydride-modified polyethylene in the thermoplastic resin composition of Example <NUM> was changed to the type shown in Table <NUM> described below. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the peroxyketal each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the dialkyl peroxide B each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the diacyl peroxide each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the dialkyl peroxide C each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the alkyl peroxyester each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the composition in the thermoplastic resin composition of Example <NUM> was changed to <NUM> parts by mass of the cellulose, <NUM> parts by mass of the maleic anhydride-modified polyethylene A, and <NUM> parts by mass of the monoperoxycarbonate each based on <NUM> parts by mass of the high density polyethylene. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the maleic anhydride-modified polyethylene A and the organic peroxide were not used. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A pellet of a cellulose-reinforced thermoplastic resin composition was produced in the same manner as in Example <NUM>, except that the organic peroxide was not used. Thereafter, a test specimen as a lamp body provided with a resin part for evaluating tensile strength was prepared using this pellet.

A test specimen as a speaker unit provided with a resin part for evaluating tensile strength was prepared with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION] using the pellet of the cellulose-reinforced thermoplastic resin composition produced in Example <NUM>.

Test specimens as speaker units each provided with a resin part for evaluating tensile strength were each prepared using each of the cellulose-reinforced thermoplastic resin compositions produced in Examples <NUM> to <NUM> in the same manner as in Example <NUM>.

A test specimen as a speaker unit provided with a resin part for evaluating tensile strength was prepared using the cellulose-reinforced thermoplastic resin composition produced in Comparative Example <NUM> in the same manner as in Example <NUM>.

A test specimen as a connection box and a connector each provided with a resin part for evaluating tensile strength was prepared with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION] using the pellet of the cellulose-reinforced thermoplastic resin composition produced in Example <NUM>.

Test specimens as connection boxes and connectors each provided with a resin part for evaluating tensile strength were each prepared using each of the cellulose-reinforced thermoplastic resin compositions produced in Examples <NUM> to <NUM> in the same manner as in Example <NUM>.

A test specimen as a connection box and a connector each provided with a resin part for evaluating tensile strength was prepared using the cellulose-reinforced thermoplastic resin composition produced in Comparative Example <NUM> in the same manner as in Example <NUM>.

A test specimen as a pulley provided with a resin part for evaluating tensile strength was prepared with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION] using the pellet of the cellulose-reinforced thermoplastic resin composition produced in Example <NUM>.

Test specimens as pulleys each provided with a resin part for evaluating tensile strength were each prepared using each of the cellulose-reinforced thermoplastic resin compositions produced in Examples <NUM> to <NUM> in the same manner as in Example <NUM>.

A test specimen as a pulley provided with a resin part for evaluating tensile strength was prepared using the cellulose-reinforced thermoplastic resin composition produced in Comparative Example <NUM> in the same manner as in Example <NUM>.

A test specimen as a film for a house, the film provided with a resin part for evaluating tensile strength, was prepared with an injection molding machine [ROBOTSHOT α-30C manufactured by FANUC CORPORATION] using the pellet of the cellulose-reinforced thermoplastic resin composition produced in Example <NUM>.

Test specimens as films for a house, the films each provided with a resin part for evaluating tensile strength, were each prepared using each of the cellulose-reinforced thermoplastic resin compositions produced in Examples <NUM> to <NUM> in the same manner as in Example <NUM>.

A test specimen as film for a house, the film provided with a resin part for evaluating tensile strength, was prepared using the cellulose-reinforced thermoplastic resin composition produced in Comparative Example <NUM> in the same manner as in Example <NUM>.

A test specimen as a film for a house, the film provided with a resin part for evaluating tensile strength, was prepared using the cellulose-reinforced thermoplastic resin composition produced in Comparative Example <NUM> in the same manner as in Example <NUM>.

Obtained results are shown together in Tables <NUM> to <NUM> below. It is to be noted that blanks in each material component in the tables indicate that the material component was not used, or was not evaluated because the material component was not used.

As it is clear from Tables <NUM> to <NUM> above, all of the test specimens of the lamp bodies, the speaker units, the connection boxes and the connectors, the pulleys, and the films for a house each provided with a resin part formed from the cellulose-reinforced thermoplastic resin compositions obtained by heating and kneading the thermoplastic resin compositions of Examples <NUM> to <NUM> of the present invention achieved a tensile strength of <NUM> MPa or more, the tensile strength measured in accordance with JIS K <NUM>, and, on the other hand, exhibited a higher tensile strength than the test specimens of the lamp bodies, the speaker units, the connection boxes and the connectors, the pulleys, and the films for a house each provided with a resin part of Comparative Examples <NUM> to <NUM>. From this fact, it is found that the thermoplastic resin compositions of Examples <NUM> to <NUM> in which cellulose is uniformly dispersed and contained, and the cellulose-reinforced thermoplastic resin compositions obtained using the thermoplastic resin compositions have an action capable of improving the mechanical strength of a molded material. In addition, in Examples <NUM> to <NUM>, the thermoplastic resin compositions and the cellulose-reinforced thermoplastic resin compositions each having such an action were used, and therefore a lamp body, a speaker unit, a connection box and a connector, a pulley, a film for a house each provided with a resin part having an improved mechanical strength were enabled to be prepared.

Claim 1:
A molded article comprising a resin part formed with a cellulose-reinforced thermoplastic resin composition, the cellulose-reinforced thermoplastic resin composition comprising an ester-bonded composite resin of a hydroxy group of cellulose and a polyolefin resin having a carboxy group and a crosslinked structure, wherein
a content of a cellulose component in the ester-bonded composite resin is <NUM> to <NUM>% by mass, and
a tensile strength of a resin molded body formed with the cellulose-reinforced thermoplastic resin composition measured in accordance with JIS K <NUM> is <NUM> MPa or more;
wherein the polyolefin resin having a carboxy group and a crosslinked structure is a polyolefin resin having a crosslinked structure such that a carbon atom in a main chain of the polyolefin resin modified by grafting an unsaturated carboxylic acid or an anhydride thereof and a carbon atom in a main chain of a polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof are bonded at two or more sites;
wherein the molded article is a lamp body of a lighting appliance, a speaker unit, a connection box, a connector or a pulley:
wherein the molded article is obtained by heating and kneading the thermoplastic resin composition comprising <NUM> to <NUM> parts by mass of cellulose based on <NUM> parts by mass of a thermoplastic resin; and an organic peroxide at a temperature where the organic peroxide existing in the composition decomposes or higher, and wherein the thermoplastic resin comprises the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof and the polyolefin resin modified with an unsaturated carboxylic acid or an anhydride thereof;
wherein the cellulose is a fiber and the hydroxyl group is on the surface; and
wherein the polyolefin resin not modified with an unsaturated carboxylic acid or an anhydride thereof is a polyethylene resin, wherein the polyethylene is selected from an ethylene homopolymer and an ethylene-α-olefin copolymer, wherein the α-olefin is <NUM>-butene, <NUM>-pentene, <NUM>-hexene or <NUM>-octene.