Resin composition having nacreous gloss

A resin composition having a nacreous gloss comprising (i) a polyvinyl chloride resin and (ii) a polystyrene resin or a high impact polystyrene resin is provided. This composition can be advantageously molded into any article and provide an excellent nacreous gloss thereto.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a resin composition having a nacreous 
gloss and capable of being molded by, for example, blow molding, vacuum 
molding, or biaxial oriented blow molding. The present resin composition 
is especially convenient for application in the fields of, for example, 
wrapping containers such as cosmetic containers and detergent containers, 
framing materials such as protective frames for cosmetic containers and 
soap containers, vacuum molded articles such as blister wrapping and PTP 
(i.e., Press Through Pack) wrapping, and decorative molded articles such 
as housing and building materials. 
2. Description of the Related Art 
In the conventional method, a nacreous gloss is given to molded articles 
such as the above-mentioned wrapping containers, framing materials, vacuum 
molded articles, and housing or building materials by using nacreous gloss 
providing agents such as fish scale guanine, talc flake powder, and 
various lead salt, mica, or titanium pearling agents in the form of flaky 
crystals. These agents are generally coated, as a coating composition, on 
the surface of the intended articles or are blended into the intended 
articles. However, since nacreous gloss providing agents in the form of 
powder are present on or near the surface, a desired transparent or clear 
nacreous gloss is not obtained by this method. As other methods of 
providing a nacreous gloss, JP-B-43-13384 (Kokoku), JP-B-46-31467 
(Kokoku), and JP-A-51-41749 (Kokai) propose various resin compositions 
having a nacreous gloss. According to these proposals, polycarbonate 
resins, methyl methacrylate resins, styrene-acrylonitrile resins, or 
polyacryl resins and polyolefin or polystyrene resins are used in the 
resin compositions. But a resin composition having a nacreous gloss 
containing vinyl chloride resins as a main constituent was not known in 
the art. Furthermore, the applications of the above-proposed conventional 
resin compositions giving a nacreous gloss to molded articles are limited, 
due to the properties of the resins. For example, nacreous resin 
compositions containing polycarbonate resins and methyl methacrylate 
resins can be used only in injection molding, and thus sheet molded 
articles having a thin wall thickness and molded bottles having a thin 
wall thickness, etc., cannot be produced from these resin compositions, 
although they can be used as thick covering materials or container 
materials. 
SUMMARY OF THE INVENTION 
Accordingly, the objects of the present invention are to eliminate the 
above-mentioned disadvantages in the conventional nacreous resin 
compositions and to provide a nacreous resin composition containing as a 
main constituent a vinyl chloride resin, which can be molded to a desired 
article by any molding technique to obtain, for example, thick covering 
materials and container materials by injection molding and sheet molded 
articles and bottles having a thin wall thickness by blow molding, vacuum 
molding, or biaxially oriented blow molding. 
Other objects and advantages of the present invention will be apparent from 
the following description. 
In accordance with the present invention, there is provided a resin 
composition having a nacreous gloss comprising (i) a polyvinyl chloride 
resin and (ii) a polystyrene resin or an impact resistant polystyrene 
resin. This nacreous resin composition can be advantageously used in blow 
molding, vacuum molding, or biaxially oriented blow molding. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The polyvinyl chloride resins usable as component (i) in the present 
invention are polyvinyl chloride homopolymer and polyvinyl chloride 
compolymers (e.g., copolymers of e.g., 80% or more of vinyl chloride with 
a minor amount of vinyl acetate, vinylidene chloride, (meth)acrylic acid 
or the esters thereof, maleates, or acrylonitrile) conventionally used in 
the resin compositions. Typical examples of such polyvinyl chloride resins 
are those having an average degree of polymerization of 400 to 3000. 
Especially, polyvinyl resins having an average degree of polymerization of 
400 to 1300, preferably 600 to 1300 are suitable for use as a blow molding 
or biaxially oriented blow molding resin and those having an average 
degree of polymerization of 700 to 3000, preferably 700 to 1300 are 
suitable for use as a vacuum molding resin. 
The polystyrene resins usable as component (ii) in the present inventions 
are those conventionally used in the art including, for example, general 
grade, good flowability grade, heat resistant grade, and high gloss grade 
polystyrene resins, preferably having a weight average molecular weight of 
140,000 to 300,000, more preferably 150,000 to 280,000. Furthermore, the 
impact resistant polystyrene resins, which have been developed to improve 
the impact resistance of polystyrene, also can be used as the component 
(ii) in the present nacreous resin composition. These impact resistant 
polystyrene resins include copolymers and mixtures of polystyrene and 
synthetic rubbers such as polybutadiene, and are called high impact 
polystyrenes or transparent high impact polystyrene resins depending upon 
the degree of copolymerization or mixing. Typical examples of the 
commercially available high impact polystyrenes are Denka HI-G-1-301 
(Trademark, available from Denki Kagaku Kogyo K.K., Japan) and HI styron 
470 available from Asahi Chemical Industry K.K., Japan. Typical examples 
of the commercially available transparent impact resistant polystyrenes 
are Clearen 750L and 730L (Trademark, both available from Denki Kagaku 
Kogyo K.K., Japan). The preferable molecular weight of the impact 
resistant polystyrene resins is 150,000 to 200,000. 
Although there are no critical limitations to the compounding ratio of the 
polyvinyl chloride resin and the polystyrene or impact resistant 
polystyrene resins in the present nacreous resin composition, the 
preferable amount of the polystyrene or impact resistant polystyrene 
resins is 4 to 30 parts by weight, especially 5 to 25 parts by weight, 
based on 100 parts by weight of the polyvinyl chloride resin. When the 
amount of the polystyrene or impact resistant polystyrene resin is less 
than 4 parts by weight, the desired nacreous gloss is not obtained. 
Conversely, when the amount of the polystyrene or impact resistant 
polystyrene resin is more than 30 parts by weight, the blow moldability 
thereof is decreased. 
Furthermore, according to the present invention, the impact resistance can 
be advantageously increased by formulating a resin modifier into the 
polyvinyl chloride resin. Examples of such resin modifiers are transparent 
ABS resins (i.e., thermoplastic resins composed of acrylonitrile, 
butadiene, and styrene) such as JSR ABS-55NP (Trademark, commercially 
available from Japan Synthetic Rubber Co., Ltd., Japan) and MBS resins 
(i.e., graft terpolymers of butadiene, styrene, and methyl methacrylate) 
such as Metablen 202 (Trademark, commercially available from Mistubishi 
Rayon Co., Ltd., Japan). The ABS resins are described in, for example, 
"ABS Resins", published by Kobunshi Gakkai and sold by Maruzen K.K., 
Japan, and the MBS resins are described in, for example, "Functional 
Acrylic Resins" by Eizo Oomori, published by K.K. Techno System, Japan. 
These resin modifiers are preferably formulated into the polyvinyl resin 
in an amount of 25 parts by weight or less, based on 100 parts by weight 
of the polyvinyl chloride resin. More specifically, the resin modifiers 
are preferably formulated in an amount of less than 5 parts by weight 
based on 100 parts by weight of the polyvinyl chloride resin when used in 
vacuum molding, and in an amount of 5 to 25 parts by weight based on 100 
parts by weight of the polyvinyl chloride when used in blow molding or 
biaxially oriented blow molding. 
Furthermore, the nacreous resin compositions according to the present 
invention may contain any conventional ingredients in addition to the 
above-mentioned components. Examples of such conventional ingredients are 
stabilizers for polyvinyl chloride such as organobutyl tin maleate, 
organobutyl tin laurate, calcium soap, barium salt, mercaptide type 
organic tin compounds; lubricants such as stearyl alcohol, stearic acid, 
fatty acid amides, hydrocarbons, and natural waxes; coloring agents; and 
the like. Thus, molded articles having an excellent nacreous gloss and an 
excellent appearance and stability can be obtained according to the 
present invention. 
As mentioned above and as illustrated in the following Examples and 
Comparative Examples, the nacreous resin compositions according to the 
present invention can be molded into any desired molded article having an 
excellent and deep transparent or clear nacreous gloss. This unexpected 
nacreous gloss is believed to be obtained from the irregular reflection. 
For example, the present nacreous resin compositions can be molded into 
thick covering materials and container materials by injection molding, and 
further, into sheet molded articles and bottles having a thin wall 
thickness by blow molding and vacuum molding. These molded articles having 
a thin wall thickness cannot be molded from the conventional nacreous 
resin compositions described above. Furthermore, the bottles or other 
articles obtained from biaxially oriented blow molding have an improved 
strength and gloss.

EXAMPLES 
The present invention now will be further illustrated by, but is by no 
means limited to, the following Examples, in which the composition amounts 
used are based on "parts by weight". 
EXAMPLES 1 to 9 
The nacreous resin compositions listed in Table 1 were prepared by 
thoroughly mixing the ingredients listed in Table 1. The molded articles 
obtained from the resultant nacreous resin compositions were 
organoleptically evaluated under the following criteria: 
A. Nacreous gloss 
o: Excellent nacreous gloss 
.DELTA.: Poor nacreous gloss 
x: Substantially no nacreous gloss 
B. Moldability 
The sample composition was vacuum molded after heating the sample sheet 
having a thickness of 0.5 mm at a temperature of 100.degree. C. to 
125.degree. C. for 5 to 8 seconds when the amount of ABS or MBS resin was 
5 parts or less based on 100 parts of the polyvinyl chloride resin, and 
blow molded to 240 ml bottles having a size of 64 mm.times.35 mm 
.times.185 mmH at a resin temperature of 200.degree. to 207.degree. C., 
when the amount of ABS or MBS resin was more than 5 parts based on 100 
parts of the polyvinyl chloride resin. The molded articles were evaluated 
under the following criteria. 
o: Good moldability 
.DELTA.: Fair moldability 
x: Poor moldability 
The evaluation results are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Example No. 
1 2 3 4 5 6 7 8 9 
__________________________________________________________________________ 
Composition (parts) 
Vinyl chloride*.sup. 1 
100 
100 
100 
100 
100 
100 
100 
100 
100 
(.sup.--P*.sup.2) 
(800) 
(800) 
(800) 
(700) 
(700) 
(700) 
(700) 
(800) 
(700) 
Polystyrene*.sup. 3 
15 10 25 20 5 -- -- -- -- 
Impact resistant 
-- -- -- -- -- 5 25 10 15 
polystyrene*.sup. 4 
Resin modifier 
ABS*.sup. 5 
-- -- -- -- -- -- -- 15 5 
MBS*.sup.6 
-- -- 5 10 15 25 15 -- 20 
Stabilizer 
Organic tin maleate 
2 2 2 2 2 2 2 2 2 
Organic tin laurate 
1 1 1 1 1 1 1 1 1 
Lubricant 
Stearyl alcohol 
1 1 1 1 1 1 1 1 0.5 
Stearic acid 
-- 0.5 
0.5 
0.5 
0.5 
0.5 
0.5 
0.5 
0.5 
Evaluation result 
Nacreous gloss 
o o o o o .DELTA. 
o o o 
Moldability 
o o o o o .DELTA. 
o o o 
__________________________________________________________________________ 
Note: The compositions shown in Table are in terms of "parts" based on 10 
parts of vinyl chloride (i.e., "PHK"). 
*.sup.1 BINIKURON 4000 LL (-p = 700) and 3000 L (-p = 800) available from 
Mitsui Toatsu Chemicals, Inc. 
*.sup.2 Average degree of polymerization 
*.sup.3 Denka Styrol GP1 having a weight average molecular weight of 
200,000 available from Denki Kagaku Kogyo K.K. 
*.sup.4 Denka Styrol HIG-1-301 having a weight average molecular weight o 
160,000 available form Denki Kagaku Kogyo K.K. 
*.sup.5 JSR ABS55NP available from Japan Synthetic Rubber Co., Ltd. 
*.sup.6 Metablen C 202 available from Mitsubishi Rayon Co., Ltd. 
COMATIVE EXAMPLE 1 
The polyvinyl chloride resin having an average degree of polymerization of 
700 used in Example 1 was molded, without formulating a polystyrene or an 
impact resistant polystyrene therein, into bottles by blow molding. 
However, the resultant bottles did not have a nacreous gloss. 
COMATIVE EXAMPLE 2 
An attempt was made to blow mold the polyvinyl chloride having an average 
degree of polymerization of 700, after formulating therein 30 parts, based 
on 100 parts of the polyvinyl chloride resin, of the polystyrene used in 
Example 1 or the high impact polystyrene used in Example 8. However, the 
resin composition was too soft, and thus blow molding thereof was 
impossible. 
EXAMPLE 10 to 17 
The nacreous resin compositions listed in Table 2 were prepared by 
thoroughly mixing the ingredients listed in Table 2. The compositions were 
blow molded in Examples 10 to 13 and vacuum molded, in Examples 14 to 17, 
both in the same manner as in Examples 1 to 9. The molded articles 
obtained from the resultant nacreous resin compositions were 
organoleptically evaluated under the same criteria as used in Examples 1 
to 9. 
The evaluation results are shown in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Example No. 
10 11 12 13 14 15 16 17 
__________________________________________________________________________ 
Composition (parts) 
Vinyl chloride*.sup.1 
100 
100 
100 100 100 100 100 100 
(.sup.--P.sup.*1) 
(400) 
(520) 
(1100) 
(1300) 
(1300) 
(1300) 
(2000) 
(2800) 
Polystyrene*.sup.1 
20 20 -- -- -- 20 -- 20 
Impact resistant 
-- -- 20 20 20 -- 20 -- 
polystyrene*.sup.1 
Resin modifier 
MBS*.sup.1 
15 15 15 15 15 -- 5 5 
Stabilizer 
Organic tin maleate 
2 2 2 2 2 2 2 2 
Organic tin laurate 
1 1 1 1 1 1 1 1 
Lubricant 
Stearyl alcohol 
1 1 1 1 1 1 1 1 
Stearic acid 
0.5 
0.5 
0.5 0.5 0.5 0.5 0.5 0.5 
Evaluation result 
Nacreous gloss 
o o o o o o o o 
Moldability 
.DELTA. 
.DELTA. 
o .DELTA. 
o o .DELTA. 
.DELTA. 
__________________________________________________________________________ 
*.sup.1 : See footnote of Table 1