Abstract:
Compositions comprising homopolymers or copolymers containing repeat units derived from α-methylenelact(ones)(ams) such as α-methylenebutyrolactones and an inorganic filler such as alumina trihydrate are described. The decorative sheets and articles made from these compositions may have one or more of higher thermal resistance, higher hardness, higher scratch and mar resistance, faster polymerization rates, antimicrobial properties, lower coefficient of thermal expansion and, owing to a higher refractive index, a higher transparency.

Description:
FIELD OF INVENTION  
         [0001]    Filled polymer compositions, and more particularly, aesthetically pleasing polymeric articles such as decorative surface materials made from homo- or copolymers of an α-methylene lact(one)(am) and an alkyl acrylate monomer, filled with an alumina trihydrate filler are described.  
         TECHNICAL BACKGROUND  
         [0002]    Filled plastics, and various methods for their manufacture constitute a well developed art. Especially, articles formed from these filled plastics via injection molding and subsequent cross-linking of the polymeric matrix comprise a large body of commercially useful products. Often, articles of manufacture are comprised of a thermoplastic or thermosetting polymeric matrix and an inert filler, such as calcium carbonate, calcium sulfate, calcium silicate, silica, clay, calcined alumina, alumina trihydrate, spheres, talc, kaolin, feldspar, baryte, mica, calcium sulfate, hollow glass spheres, ceramic materials, carbon black or carbon fiber. Other filler materials include nylon flock fibers, and polyester fibers. Articles of manufacture comprising polymeric methyl methacrylate homopolymer and an alumina trihydrate filler are disclosed in U.S. Pat. No. 3,084,068, Re.27,093, U.S. Pat. Nos. 3,847,865 and 4,107,135.  
           [0003]    Among the uses of these filled plastics are decorative solid surfacing materials such as simulated marble, kitchen sinks, bathroom sinks, table tops, counter tops, dresser tops, vanity tops, shelving, and furniture applications. Depending on the severity of these applications, properties such as toughness, temperature resistance, scratch resistance, microbial resistance, translucency, and flame resistance of the laminate surface are very important. Most of these decorative surface materials are manufactured with poly (methyl methacrylate) (hereinafter referred to as PMMA) as a matrix material with different inert fillers.  
           [0004]    PMMA offers excellent optical clarity (92% of white light) and brilliance. It remains unaffected by most household detergents, cleaning agents and solutions of inorganic acids, and alkalis. Moreover, it is amenable to forming shapes via injection molding, extrusion, and polymerization casting.  
           [0005]    Like most other thermoplastics, PMMA exhibits a higher coefficient of thermal expansion as compared to metals. However, the most significant disadvantage of PMMA is that its thermal properties limit its use in articles. PMMA softens circa. 115° C. and its continuous service temperature is lower, approximately 95° C. Therefore, other plastic materials are used in high temperature applications. In the specific usage of decorative sheets and related articles, three limitations are observed in high performance applications: (i) ineffective ability to withstand higher temperature conditions (in the range of 100° C. through 200° C.), (ii) lower material hardness of materials with a PMMA matrix and (iii) lower scratch and mar resistance of such materials. Thus, polymeric matrix materials with good temperature resistance and/or scratch resistance and/or higher flexural modulus are desired.  
           [0006]    In the manufacture of such filled plastic articles such as decorative surfaces, monomer volatility can be an environmental hazard issue. A lower volatility monomer is usually desired.  
           [0007]    Since the refractive index of the fillers is usually high, a closer match of the refractive index of the polymer to the matrix, while preserving other properties such as clarity and weatherability is desired to create materials with a greater translucency.  
           [0008]    Copolymers of an alpha-methylene gamma-butyrolactone (hereinafter referred to as α-MBL) with various vinyl monomers are known in the literature (Kunstoffe, 87, pp 734-736, 1997; incorporated herein by reference). Making copolymers from methyl methacrylate or other monomers and an exomethylene lact(one)(am) monomer is described in U.S. Pat. No. 5,880,325.  
           [0009]    British patent 614,310 and U.S. Pat. No. 2,624,723 describe the synthesis of methylene lactone homopolymers. The British patent also mentions the possibility of additives such as fillers and coloring materials to modify the homopolymer properties. U.S. Pat. No. 3,847,865, U.S. Re. 27,903 and U.S. Pat. No. 4,107,135 describe a process where a decorative surface can be formed using PMMA as the matrix or its copolymers as the matrix, for example, ethylenically unsaturated compounds as co-monomers. These patents teach how to fabricate decorative sheet with a polymer matrix and a filler such as calcium carbonate, alumina trihydrate, nylon fiberstock, polyester fiber, silica, spheres, talc, kaolin, feldspar, baryte, mica, calcium sulfate, hollow glass spheres, ceramic materials, carbon black or carbon fiber.  
         SUMMARY OF INVENTION  
         [0010]    This invention concerns a composition comprising, a copolymer of at least one α-methylene lact(one)(am) monomer of formula (I) and at least one other free radically copolymerizable monomer, and an inorganic filler, provided that no more than 95 mole percent and not less than 1 mole percent of repeat units in said copolymer are derived from said α-methylene lact(one)(am) monomer,  
                         
 
           [0011]    wherein:  
           [0012]    n is 0, 1 or 2;  
           [0013]    X is —O— or —NR 9 —; and  
           [0014]    R 1 , R 2 , R 5 , and R 6  each of R 3  and each of R 4 , are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl, and  
           [0015]    R 9  is independently hydrogen, or hydrocarbyl or substituted hydrocarbyl.  
           [0016]    This invention also concerns, a composition, comprising an α-methylene lact(one)(am) homopolymer, and between 5% and 80% by weight of a filler, based on a total weight of said homopolymer, and said filler.  
           [0017]    This invention also concerns a composition comprising an α-methylene lact(one)(am) copolymer and between 5% and 80% by weight of a filler, based on a total weight of said copolymer and said filler.  
           [0018]    This invention also concerns a composition comprising an α-methylene lact(one)(am) homopolymer, and at least 10% by weight of alumina trihydrate based on a total weight of said homopolymer and said alumina trihydrate.  
           [0019]    This invention also concerns a composition comprising an α-methylene lact(one)(am) copolymer and at least 10% by weight of alumina trihydrate based on a total weight of said copolymer, and said alumina trihydrate.  
           [0020]    This invention also concerns a composition comprising at least one α-methylene lact(one)(am), a free radically copolymerizable monomer and an inorganic filler. This composition can optionally include a free radical initiator.  
           [0021]    This invention also describes a process for manufacturing a plastic article, comprising contacting,  
           [0022]    (a) one or more acrylate or methacrylate esters  
           [0023]    (b) one or more a-methylene lact(one)(am) monomer of the formula (I)  
                         
 
           [0024]    wherein:  
           [0025]    n is 0, 1 or 2;  
           [0026]    X is —O— or —NR 9 —; and  
           [0027]    R 1 , R 2 , R 5 , R 6 , each of R 3  and each of R 4 , are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl, and  
           [0028]    R 9  is a hydrocarbyl or a substituted hydrocarbyl,  
           [0029]    (c) at least one free radical initiator,  
           [0030]    (d) at least 10 weight percent of a filler based on total weight of the said homopolymer or copolymer and the filler,  
           [0031]    (e) optionally, one or more homopolymers or copolymers of acrylate and/or methacrylate esters,  
           [0032]    provided that said contacting is at a sufficient temperature to cause said free radical initiator to generate free radicals; and (b) is at least 1 mole percent of the total of (a) and (b).  
           [0033]    This invention also describes a process for manufacturing a plastic article, comprising contacting,  
           [0034]    (a) one or more acrylate or methacrylate esters  
           [0035]    (b) one or more a-methylene lact(one)(am) monomer of the formula (I)  
                         
 
           [0036]    wherein:  
           [0037]    n is 0, 1 or 2;  
           [0038]    X is —O— or —NR 9 —; and  
           [0039]    R 1 , R 2 , R 5 , R 6 , each of R 3  and each of R 4 , are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl, and  
           [0040]    R 9  is a hydrocarbyl or a substituted hydrocarbyl,  
           [0041]    (c) at least one free radical initiator,  
           [0042]    (d) at least 10 weight percent of alumina trihydrate based on total weight of the said homopolymer or copolymer and alumina trihydrate,  
           [0043]    (e) optionally, one or more homopolymers or copolymers of acrylate and/or methacrylate esters, provided that said contacting is at a sufficient temperature to cause said free radical initiator to generate free radicals; and (b) is at least 1 mole percent of the total composition of (a) and (b).  
         DETAILED DESCRIPTION OF THE INVENTION  
         [0044]    The following terms as used herein are defined below:  
           [0045]    By “hydrocarbyl group” is meant a univalent group containing only carbon and hydrogen. If not otherwise stated, it is preferred that hydrocarbyl groups (and alkyl groups) herein contain about 1 to about 30 carbon atoms.  
           [0046]    By “substituted hydrocarbyl” is meant a hydrocarbyl group which contains one or more substituent groups which are inert under process conditions to which the compound containing the group is subjected. The substituent groups also do not substantially interfere with the process. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of “substituted” are heteroatomic rings. In substituted hydrocarbyl all of the hydrogens may be substituted, as in trifluoromethyl.  
           [0047]    By “functional group” is meant a group other than hydrocarbyl or substituted hydrocarbyl which is inert under the process conditions to which the compound or polymer containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound or polymer in which they are present may take part in. Examples of functional groups include halo (fluoro, chloro, bromo, and iodo), and ether groups such as —OR 22  wherein R 22  is hydrocarbyl or substituted hydrocarbyl.  
           [0048]    By “copolymerizable under free radical conditions” is meant that the monomers involved are known to copolymerize under free radical polymerization conditions. Preferably, the monomers involved are vinyl monomers. The free radicals may be generated by any of the usual processes, for example thermally from radical initiators such as peroxides or azonitriles, by UV radiation using appropriate sensitizers etc., and by ionizing radiation. The copolymerization may be done in any number of known ways, for example bulk and solution polymerization. These polymers may be prepared by various types of processes, such as continuous, batch and semibatch, which are well known in the art. Many combinations of free radically copolymerizable monomers are known, see for instance J. Brandrup, et al., Ed., Polymer Handbook, 4 th  Ed., John Wiley &amp; Sons, New York, 1999, p. II/181-II/308.  
           [0049]    By “copolymer of α-methylene lact(one)(am)” is meant that at least 1 mol % of the repeat unit in the copolymer are derived from the homopolymer of an α-methylene lact(one)(am) of the general formula  
                         
 
           [0050]    wherein X and R 1  through R 6  and R 9  are as defined above. In a preferred structure of I and corresponding polymeric repeat units:  
           [0051]    n is 0; and/or  
           [0052]    R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably all are hydrogen; and/or  
           [0053]    X is —O— or —NR 9 — wherein R 9  is hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably X is —O—.  
           [0054]    By “inorganic filler” is meant a finely divided inorganic material which may cause property changes to the final article into which it is incorporated. Examples of inorganic fillers are calcium carbonate, calcium sulfate, calcium silicate, silica, clay, calcined alumina, alumina trihydrate, glass fibers, carbon fibers, titanium dioxide, spheres, talc, kaolin, feldspar, baryte, mica, hollow glass spheres, ceramic materials, and carbon black.  
           [0055]    Decorative solid surface materials may be manufactured using a PMMA matrix and an inorganic filler, with appropriate coupling agents, initiators, etc. However, several properties of the decorative surface materials and sheets can be improved to better serve their application purpose. Herein, the properties of the composition with higher toughness and hardness improve scratch and impact resistance. A higher temperature resistance can expand the utility of the articles, for example, kitchen countertop applications would benefit from improved temperature resistance. Localized heating of the surface in table and kitchen tops can be very high when a hot object in placed on it. A polymer having a higher glass transition temperature (Tg) in this situation can help reduce damage to the surface.  
           [0056]    The properties of the composition are improved herein by improving the matrix polymer. Described is a product and process for fabrication from a composition to give the matrix material which is a copolymer of α-methylene lact(one)(am) and an inert filler.  
           [0057]    The α-methylene lact(one)(am) repeat unit(s) in the copolymer composition is(are) derived from the monomer  
                         
 
           [0058]    wherein X and R 1  through R 6  are as defined above. In a preferred structure:  
           [0059]    n is 0; and/or  
           [0060]    R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably all are hydrogen; and/or  
           [0061]    X is —O— or —NR 9 — wherein R 9  is hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably X is —O—.  
           [0062]    In a particularly preferred structure, n is 0, X is —O— and R 1 , R 2 , R 5  and R 6  are hydrogen, or n is 0, X is —O—, R 6  is methyl, and R 1 , R 2  and R 5  are hydrogen. This structure is also known as α-methylene-γ-butyrolactone. For other preferred structures, see U.S. Pat. No. 5,880,235, which is hereby included by reference, at column 4, line 44 to column 8, line 59.  
           [0063]    The free radically copolymerizable monomer in the composition of the copolymer may have the formula  
                         
 
           [0064]    wherein R 14  is hydrogen or methyl, and R 15  is hydrocarbyl or substituted hydrocarbyl, preferably alkyl, R 16  is hydrogen or methyl and R 17 , R 18 , R 19 , R 20  and R 21  are each independently hydrogen, hydrocarbyl substituted hydrocarbyl or a functional group. In a preferred (II), R 14  and R 15  are both methyl (methyl methacrylate), and in a preferred (III), R 16 , R 17 , R 18 , R 19 , R 20  and R 21  are all hydrogen (styrene). In another preferred copolymer, these repeat units are derived from methyl methacrylate and an alkyl acrylate, preferably ethyl acrylate. The free radically copolymerizable monomer may also include acrylonitrile, acrylic acid or or methacrylic acid.  
           [0065]    Fillers of the invention can include, but are not limited to, one or more of the following:  
                                                                       Aluminum   Hydroxide   Barium   Hydroxide           Oxide       Oxide           Sulfate       Sulfate           Phosphate       Phosphate           Silicate       Silicate       Calcium   Sulfate   Magnesium   Sulfate           Silicate       Silicate           Phosphate       Phosphate           Carbonate       Hydroxide           Hydroxide           Oxide           Apatite       Glass   Bubbles   Clays   Kaolin           Microspheres            Montmorillonite                Fibers               Bentonite           Beads       Pyrophyllite           Flakes           Powder       Additional:           Mica       Cristobalite           Powder Talc       Wood flour           Gypsum       Feldspar           Titanium Dioxide       Carbon black           Quartz       Zircon           Diatomaceous earth       Borax           Silica       Wollastonite           Calcite           Carbon fiber           Ceramic Microspheres       Calcined alumina           Baryte                  
 
           [0066]    In a preferred composition, an inorganic filler may be a mixture of alumina trihydrate with any of the other inorganic fillers listed here. In a particularly preferred composition, inorganic filler is alumina trihydrate. The filler can also be an organic filler which includes, but is not limited to nylon fiber, polyester fiber.  
           [0067]    A preferred content of the filler is about 5% to about 80% by weight of the total article. In a more preferred combination, the filler content is in the range of about 40% to about 60% by weight. A preferred content of the polymer in the final article is about 40% to about 60%, by total weight of the polymer and alumina trihydrate.  
           [0068]    A preferred content of alumina trihydrate filler is about 10% to about 80% by weight of the total article. In a more preferred combination, the alumina trihydrate content is in the range of about 40% to about 60% by weight. A preferred content of the polymer in the final article is about 40% to about 60%, by total weight of the polymer and alumina trihydrate.  
           [0069]    The α-methylene lact(one)(am) repeating unit weight content in the total polymer present in the composition is preferred in the range of about 1% to about 95%, preferably about 30% to about 40% of the total polymer weight, with a preferable minimum amount of about 2% or a more preferable minimum amount of about 5% or a more preferable amount of about 10% or a further preferable amount of about 20% and preferable maximum amount of about 80% or a more preferable maximum amount of about 65% and a further preferable maximum amount of about 50% and a more preferable amount of about 40%, such that any preferable minimum amount can be combined with any preferable maximum amount.  
           [0070]    The content of the repeat units derived from the free radically copolymerizable monomer(s) is preferred from about 5% to about 99%; more preferably about 60% to about 70% of the copolymer. In a preferred composition, the free radically copolymerizable monomer is methyl methacrylate. In another preferred composition, the free radically copolymerizable monomers are methyl methacrylate and an alkyl acrylate, wherein the alkyl group has 1-8 carbon atoms, more preferably ethyl acrylate or n-butyl acrylate, and/or the alkyl acrylate content is not more than about 10 mole % of the radically copolymerizable comonomer content. It is also possible to use glycidyl acrylate or methacrylate in any of the above compositions. In a particularly preferred composition, the free radically copolymerizable monomer may be a mixture of methyl methacrylate and ethyl or butyl acrylate, where the ethyl or butyl acrylate content is not more than about 5 weight % of the radically copolymerizable comonomer content in the final copolymer matrix. Such copolymers are described in U.S. Pat. No. 5,880,235, which is hereby incorporated by reference.  
           [0071]    When an α-methylene lact(one)(am) is present in a copolymer, it tends to raise the glass transition temperature (T g ). For example, in a copolymer with methyl methacrylate, the T g  will normally be above the T g  of a PMMA homopolymer.  
           [0072]    A preferred composition useful for a decorative sheet is a copolymer of at least one of α-methylene lact(one)(am) monomer and at least one of the alkyl acrylate monomer with at least 30 weight % inorganic filler, from one or more of the inorganic fillers listed previously. A particularly preferred composition is a copolymer matrix of α-methylene-γ-butyrolactone, and methyl methacrylate or a copolymer of α-methylene-γ-butyrolactone and ethyl acrylate, with at least 10 weight percent of alumina trihydrate filler.  
           [0073]    Another type of monomer that may be used is a monomer that contains more than one polymerization sites for e.g., a di- or tri-acrylate, or methacrylate, or vinyl styrene. During the polymerization, these monomers cause crosslinking of the polymer. Usually, relatively small amounts are added so that the monomer is not highly crosslinked. Included in the composition herein are those compositions where PMMA or another homo- or copolymer is present in the composition which are a mixture of PMMA or a copolymer of PMMA and alkyl acrylate.  
           [0074]    Decorative sheet compositions described herein usually have better thermal resistance compared to a composition made with a pure PMMA, see for instance Table 1 in Example 3, where the glass transition temperatures of α-MBL polymer, of PMMA and of copolymers of α-MBL and MMA are given.  
           [0075]    Another advantage that copolymerization of α-methylene lactone often imparts to the decorative sheet manufacture process is the high rate of chemical reaction (also known as cure rate). Table 1 also lists the time in minutes taken to achieve the highest temperature of reaction, by polymeric matrices with varying α-methylene lactone contents.  
           [0076]    Table 3 in Example 3 gives experimentally determined modulus of elasticity properties. An improvement in modulus of elasticity is found with an increasing α-methylene lactone content.  
           [0077]    Filled polymer compositions described herein have a better refractive index match between the polymer and the filler due to the higher refractive index of poly(MBL) compared to PMMA. This can result in materials with a greater translucency.  
           [0078]    All of the compositions herein may additionally comprise other materials commonly found in thermoplastic compositions, such as, dyes, pigments, UV stabilizers, processing aids, flame retardants, antioxidants, and antiozonants. These materials may be present in conventional amounts, which vary according to the type(s) of material(s) being added and their purpose in being added.  
           [0079]    It was found that incorporating the compositions of this invention into a solid surface material caused the solid surface material to exhibit antimicrobial/antibacterial properties. The antimicrobial/antibacterial effectiveness was tested with  Escherichia Coli  bacteria in a residual self-sanitizing test. Example 8 demonstrates that α-MBL-based decorative sheet reduced the bioburden by 3.92 logs, or greater than 99.9% reduction of bacteria as compared to the control sheet. For purposes of antimicrobial/antibacterial activity, the compositions of this invention can be incorporated into a wide array of products, such as, bathroom vanity tops, sinks, shower stalls, kitchen counter tops, solid surfaces in hospitals, nursing homes and daycare facilities, commercial and residential food preparation facilities, office supplies, and other applications where it is desirable to minimize human contact with bacteria. 
       
    
    
     EXAMPLES  
       [0080]    In the Examples the following abbreviations are used:  
         [0081]    VAZO® 67—azobis(methylbutyronitrile)  
         [0082]    DMSO—dimethyl sulfoxide  
         [0083]    MMA—methyl methacrylate  
         [0084]    α-MBL—α-methylene-γ-butyrolactone  
         [0085]    T g —glass transition temperature  
         [0086]    DMA—dynamic mechanical analysis  
         [0087]    ATH—alumina trihydrate  
         [0088]    GDMA—Glycol dimercaptoacetate  
         [0089]    PMMA—Poly(methyl methacrylate)  
         [0090]    TSA®—Trypticase® Soy Agar  
         [0091]    TSB®—Trypticase® Soy Broth  
         [0092]    MMA was obtained from Aldrich Chemical Company, Inc., Milwaukee, Wis., U.S.A. AIBN, Zonyl® UR fluorosurfactant external release coating were obtained from E. I. du Pont de Nemours &amp; Co., Wilmington, Del., U.S.A. Silastic® gasket (silicone rubber) was obtained from Dow Corning Corp., Midland, Mich., U.S.A. t-butyl peroxyneodecanoate was obtained at a 25 wt % dispersion in mineral oil (Lupersol® 10M75) from Atofina, King of Prussia, Pa. The Trypticase®soy broth and agar were obtained from Becton, Dickinson Biosciences of Franklin Lakes, N.J.  
         [0093]    Haze and transmission were measured according to ASTM D1003. The flexural modulus was measured by ASTM D790. DMA measurements were performed by ASTM 5023 with torque force of 1.2-1.4 N·m. The bar was scanned in 5 frequencies (0.3, 1, 3, 10 and 30 Hz) at 1° C./min rate from −140° C. to 180° C. The oscillation amplitude was 10 μm. Glass transition temperatures (T g ) were measured by ASTM D3418 at a heating rate of 10° C./min and the T g  was measured as the midpoint of the transition.  
       EXPERIMENT 1  
     Preparation of Filled Sheet (Thermal Cure)  
       [0094]    The following ingredients are added to a 1000 mL reaction kettle, fitted with a temperature probe, air-driven stirrer, rubber septum and a reflux condenser:  
                                       trimethylolpropane trimethacrylate   4.48 g       10% solution of poly(methyl methacrylate-co-ethyl   492.84 g        acrylate 96/4) in MMA       Pigment paste   0.53 g       t-butyl peroxyneodecanoate, 25% dispersion in mineral oil   1.79 g       VAZO 67   0.36 g                  
 
         [0095]    After mixing these ingredients, 500 g of ATH were added portionwise over a two minute interval. During the portionwise addition of the ATH, the stirring speed was increased to about 1500 rpm.  
         [0096]    After the ATH addition was complete, the stirring speed was increased to 2000 rpm and maintained for 10 min. About 2.5 g of MMA monomer was added and the mix was then evacuated at 100 Pa for two min. with 1000 rpm stirring. The mixture was poured into a casting mold constructed from two stainless metal plates (25.4 cm×25.4 cm×1.0 mm) separated by a Silastic® gasket (12.95 mm thickness). Each of the metal plates was coated with a Zonyl® UR external release coating. The casting mold was assembled using spring clamps. After bleeding a small amount of air from the cell, the sealed cell was submerged vertically in an 80° C. waterbath. Twenty min. later, the casting cell was removed from the waterbath and placed in a 120° C. circulating hot air oven for 60 min.  
       Example 1-3  
     Preparation of Filled Sheet Containing α-methylene g-butyrolactone (Thermal Cure)  
       [0097]    Three polymer syrups of 10 weight % solution of poly(methyl methacrylate-co-ethyl acrylate) (96/4 weight percent) in a MBL/MMA mixtures were made by slowly dissolving the polymer in the monomer in a reaction kettle. In the 100% MBL mixture, no acrylic odor was observed, nor was there any foaming or bubbling in the degassing step. These syrups were used to make filled acrylic sheet as described in Experiment 1. The color of these sheets was similar to the sheet of Experiment 1.  
                                     TABLE 1                           Time in minutes taken to achieve the highest temperature       of reaction and T g  of MBL/MMA filled sheet (thermal cure)                        Time to peak                   MBL/MMA   temperature           Example   (Wt %)   (min)   T g  (° C.)                       1   100/0    4.5 min   177           2   50/50   4.5 min   148           3   27/75   9.5 min   122                      
 
         [0098]    [0098]                                                           TABLE 2                           Properties of MBL/MMA filled sheet (thermal cure)                            MBL                   MMA   filled sheet       Property       ASTM   filled sheet   Example 1                    Ultimate stress   MPa   ASTM D790   58.2   51.3       Ultimate strain   %   ASTM D790   2.26   0.503       Energy to break   N.m   ASTM D790   0.411   0.061       Elastic modulus   GPa   ASTM D790   6.46   10.70                    
         [0099]    [0099]                                     TABLE 3                           DMA data on MBL/MMA filled sheets (thermal cure)            Thermal Properties   Example 1   Example 2   Example 3   100% PMMA cured               Modulus E′ @ 25° C.   10.4 GPa   8.2 GPa   7.9 GPa   7.4 GPa       Tα @ 1 Hz by   122.0° C.   77° C., 105° C.   93° C.   107° C.       DMA E″ peak       Tβ @ 1 Hz by   61.1° C., E act  =   2.0° C., E act  =   12.0° C., E act  =   16.8° C., E act  =       DMA E″ peak   96 kcal/mole   20.9 kcal/mole   19 kcal/mole   18 kcal/mole       Tβ′ @ 1 Hz by   2.6° C., E act  =       DMA E″ peak   26 kcal/mole       Tγ @ 1 Hz by       −100° C., E act  =   −102° C., E act  =   −105° C., E act  =       DMA E″ peak       13 kcal/mole   14 kcal/mole   13 kcal/mol                    
         [0100]    Tα is the highest relaxation temperature corresponding to the glass transition, Tβ and Tβ′ are the next lowest relaxation temperatures believed to be from the lactone ring motion, Tγ is the lowest observed relaxation temperature believed to be the motion of —CH 3 .  
       Example 4  
     Preparation of Filled Sheet Containing Methylene Butyrolactone (Chemical Cure, MBL 10 Weight % of Available Monomer)  
       [0101]    The following ingredients were sequentially added to a 2000 mL reaction kettle, fitted with a temperature probe, air-driven stirrer, rubber septum and a reflux condenser:  
                                                       t-Butyl peroxymaleic acid   9.81 g           Pearl grey pigment paste   0.91 g           Dioctyl sodium sulfosuccinate   3.92 g           Trimethylolpropane trimethacrylate   6.54 g           MMA   56.22 g            α-MBL   52.96 g            24% solution of poly(methyl methacrylate) in MMA   544.6 g                       
 
         [0102]    After mixing these ingredients for 1 min at room temperature, 1020 g of ATH were added portionwise over a 2 min interval and then stirred for 10 min.  
         [0103]    About 5.0 g of MMA was added. The mix was then evacuated at 10 KPa with stirring. Vacuum was lowered to 20 KPa with stirring, then gently warmed to 40° C. using a waterbath. The following ingredients were sequentially injected in rapid succession:  
                                       Demineralized water   2.04 g       Calcium hydroxide dispersion in butylmethacrylate monomer   2.81 g       Glycol dimercaptoacetate (GDMA)   1.43 g                  
 
         [0104]    The addition of the GDMA was considered the starting point in time of experiment. The slurry was mixed at 41° C. for 10 s. Mixing was discontinued and the vacuum released and poured into a 12.6 mm tilted adiabatic casting mold.  
       Example 5  
     Preparation of Filled Sheet Containing Methylene Butyrolactone (Chemical Cure, MBL 20% of Available Monomer)  
       [0105]    The recipe of Example 4 was repeated with the following changes only:  
                                                       MMA    3.26 g           MBL   105.92 g                      
 
       Example 6  
     Preparation of Filled Sheet Containing Methylene Butyrolactone (Chemical Cure, MBL 5% of Available Monomer)  
       [0106]    The recipe of Example 4 was repeated with the following changes only:  
                                                       MMA   82.70 g           MBL   26.48 g                      
 
       Example 7  
     Preparation of Filled Sheet Containing Methylene Butyrolactone (Chemical Cure, MBL 15% of Available Monomer)  
       [0107]    The recipe of Example 4 was repeated with the following changes only:  
                                                       MMA   29.74 g           MBL   79.44 g                      
 
         [0108]    [0108]                                 TABLE 4                           Time in minutes taken to achieve the highest temperature       of reaction and T g  of MBL/MMA filled sheet, chemical cure.                        Time to achieve               Peak   Peak               Temperature   Temperature (+/−       Example   MBL/MMA Wt %   ° C. (+/−2° C.)   0.5 min)               6    5/95   129   13 min        4   10/90   131   10.5 min         7   15/85   133   7 min       5   20/80   133   6 min                    
         [0109]    [0109]                                                                   TABLE 5                           Properties of MBL/MMA filled sheet, chemical cure (ASTM D790)            Property       PMMA sheet   Ex 4   Ex 6   Ex 7                    Ultimate stress   MPa   79.8   67.7   67.6   66.8       Ultimate strain   %   1.06   0.88   0.90   0.83       Energy to break   J   0.441   0.315   0.311   0.284       Elastic modulus   GPa   9.46   9.57   8.99   9.57                    
       Example 8  
     Antimicrobial Activity of α-MBL Filled Sheet  
       [0110]    MBL filled acrylic sheet from Example 1 was cut in 5×5 cm tiles. Corian® control pieces were 6×6 cm. The test organism was  Escherichia coli,  ATCC #25922. The inoculum was prepared by diluting an overnight culture (grown in Trypticase® Soy broth) 1:1,000 (v/v) in dilute phosphate buffer. All polished surfaces of the tiles were wiped with isopropyl alcohol and cheesecloth to clean the surface. A 0.5 mL aliquot of the inoculum was pipetted and spread over the surface of each Corian® tile and a 0.42 mL aliquot was spread over the surface of each MBL tile. The inoculated tiles were each placed in a closed, sterile glass petri plate and placed in open fiberglass trays. The samples were incubated at 25° C. and 85% RH. At the end of the incubation time, the tiles were washed twice with enough sterile phosphate buffer to bring the combined inoculum and wash buffer to 10 mL. The tiles were then wiped dry with a piece of sterile gauze to ensure that the inoculum was wiped completely from the tile. The viable bacteria were then enumerated using a standard serial-dilution spread-plating technique on Trypticase® soy agar (TSA). The lower limit of detection with this method is 1.0×10 2  CFU/mL (Colony Forming Units per milliliter). The maintenance of antimicrobial activity of the tiles is expressed as the t value where, 
         t=log CFU/mL of control tile−log CFU/mL of test tile (both at the same exposure time) 
         [0111]    The MBL tiles demonstrated significant antibacterial activity in 5 h of exposure to  E. coli  and reduced the bioburden by 3.92 logs (&gt;99.9% reduction) compared to the Corian® control.