JP2000212370A - (meth)acrylic molding material and molded product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide (meth)acrylic molding materials having good appearance when made into molded articles and having a low degree of thermal discoloration. SOLUTION: This (meth)acrylic molding material is characterized by including (a) aluminum hydroxide having 80-97% whiteness in (b) (meth)acrylic syrup comprising, as main ingredients, (i) a vinyl monomer mixture composed of a (meth)acrylate and styrene as essential ingredients and (ii) a (meth)acrylic polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a (meth) acrylic molding material and a molded article using the same, and more particularly, to a (meth) acrylic molded article having a good appearance and a low degree of thermal discoloration when formed into a molded article. The present invention relates to an acrylic molding material and a molded article using the same.

[0002]

2. Description of the Related Art A (meth) acrylic syrup containing a (meth) acrylic polymer and a vinyl monomer as main components provides a molded article having good weather resistance and appearance. It has been conventionally used as a molding material.
As such (meth) acrylic syrup, conventionally, for example, (meth) acrylic syrup obtained by dissolving polymethyl methacrylate in methyl methacrylate, and (meth) acrylic syrup obtained by partially polymerizing methyl methacrylate are widely used. Was used.

On the other hand, aluminum hydroxide as an inorganic filler has excellent properties such as transparency, chemical stability and flame retardancy, and has a lower hardness than silica or the like. Since it has little wear in a mold, it has been widely used as a molding material such as artificial marble. Among the aluminum hydroxides, those having high whiteness of 98 or more have been particularly preferably used because the obtained molded article has little coloring and gives a sense of quality.

[0004]

However, when molding is performed using the above (meth) acrylic syrup, the curing speed is too high, and the appearance (surface smoothness and blurring) of the molded product may deteriorate. As a means for solving this problem, styrene has been conventionally added to (meth) acrylic syrup. However, if styrene is added, the performance of molded articles, especially heat discoloration resistance, becomes poor. This is noticeable when high-white aluminum hydroxide is used.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a (meth) acrylic molding material which has a good appearance when formed into a molded product and has a small degree of thermal discoloration. .

[0006]

According to the present invention, aluminum hydroxide having a whiteness in the range of 80 to 97 is converted into a (meth) acrylic acid ester and a vinyl monomer having styrene as essential components, A (meth) acrylic molding material characterized by being contained in a (meth) acrylic syrup containing a (meth) acrylic polymer as a main component. At this time, the average particle size of the aluminum hydroxide is preferably in the range of 3 to 50 microns.

Further, according to the present invention, there is provided a molded article characterized by being molded from the above (meth) acrylic molding material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies as to whether a (meth) acryl-forming material having a good appearance when formed into a molded article and having a small degree of thermal discoloration can be produced. ) Use as an essential component of the vinyl monomer of the acrylic syrup and use of aluminum hydroxide having a specific whiteness and an average particle size, so that a molded article has a good appearance and a thermal discoloration degree. The present inventors have found that a small (meth) acryl-forming material can be obtained, and have accomplished the present invention.

The whiteness of the aluminum hydroxide used in the present invention is in the range of 80 to 97, preferably in the range of 80 to 95. By using aluminum hydroxide having a whiteness of 97 or less, which is lower than that of aluminum hydroxide that has been used conventionally, it has excellent apparent stain resistance, is hardly conspicuous even when dirt is attached, The degree of discoloration due to Here, the whiteness means the Hunter whiteness of the powder.

The average particle size of the aluminum hydroxide used in the present invention is preferably in the range of 3 to 50 microns. Preferably it is in the range of 5-30 microns. If the average particle size is smaller than 3 microns, the viscosity of the (meth) acrylic syrup becomes too high when a large amount of the aluminum hydroxide is added to the (meth) acrylic syrup, and the aluminum hydroxide is uniformly dispersed in the syrup. Can be difficult. For this reason, the amount of addition must be reduced to achieve uniform dispersion. In this case, heat shrinkage at the time of curing becomes large and the appearance of the molded product may be deteriorated, but heat resistance discoloration, stain resistance and the like are not impaired.
On the other hand, if the average particle size is larger than 50 microns, the mechanical strength may be reduced or the material may be slightly tacky. In this case, the tackiness can be eliminated by increasing the amount of addition. In addition, the said average particle diameter is a pore passage type particle size distribution analyzer "CULTER MULTISIZE".
RII ".

The other physical properties of the aluminum hydroxide used in the present invention are not particularly limited.
The range is 1.8 to 2.5 m ² / g, and further 2.0 to ² .
It is desirable to be in the range of 4 m ² / g. If the specific surface area is smaller than 1.8 m ² / g, the viscosity of the syrup when added to a (meth) acrylic syrup may be reduced, resulting in poor handling properties. On the other hand, when the specific surface area is larger than 2.5 m ² / g, the viscosity of the syrup becomes too high when added to the (meth) acrylic syrup, and it may be difficult to uniformly disperse the aluminum hydroxide in the syrup. is there. Here, the specific surface area is a value obtained by a specific surface area measurement method by a low-temperature nitrogen gas adsorption (BET specific surface area measurement method). In addition, D of the aluminum hydroxide
OP oil absorption is 33 ml / 100 g or more, preferably 35
It is desirably at least 100 ml / 100 g. When the DOP oil absorption is less than 33 ml / 100 g, the viscosity at the time of filling the radical polymerizable resin is reduced, and the handling property may be deteriorated. Here, the DOP oil absorption refers to the amount of DOP (dioctyl phthalate) added little by little to 100 g of aluminum hydroxide, observation of the state while kneading the mixture, finding a point forming one lump from the dispersed state, and the ml of the DOP at that time. A number.

The aluminum hydroxide surface may be treated with a surface treating agent for the purpose of improving the dispersibility in (meth) acrylic syrup and the mechanical strength of the obtained molded article. Examples of the surface treatment agent include silane coupling agents such as methacrylic silane, acrylic silane, vinyl silane, epoxy silane, and amino silane.

The (meth) acrylic syrup used in the present invention is mainly composed of a (meth) acrylic acid ester, a vinyl monomer having styrene as essential components, and a (meth) acrylic polymer. .

First, the (meth) acrylic ester, which is an essential component of the vinyl monomer, includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
s-butyl (meth) acrylate, t-butyl (meth)
(Meth) acrylic acid alkyl esters such as acrylate, 2-ethylhexyl (meth) acrylate and lauryl (meth) acrylate; (meth) acrylic acid cycloalkyl esters such as cyclohexyl (meth) acrylate; 2-hydroxylethyl (meth) acrylate; 2
A (meth) acrylate having a hydroxyalkyl group such as hydroxylpropyl (meth) acrylate; glycerin mono (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate (Meth) of polyhydric alcohols such as
Acrylate; (meth) acrylate of high molecular weight glycol such as polyethylene glycol mono (meth) acrylate; ε-caprolactone ring-opened adduct to 2-hydroxyethyl (meth) acrylate or γ to 2-hydroxyethyl (meth) acrylate A (meth) acrylate having a hydroxyl group such as a ring-opening adduct of butyrolactone; a basic (meth) acrylate such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ethylene glycol di (meth) acrylate; ) Acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth)
Polyfunctional (meth) acrylates such as acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate; polyfunctional (meth) acrylic such as epoxy (meth) acrylates Acid esters. These (meth) acrylic acid esters may be used alone or as a mixture of two or more.

Among the above-mentioned compounds, methyl methacrylate and a (meth) acrylate ester containing methyl methacrylate as a main component are particularly preferable. By using methyl methacrylate as the main component, the cured product obtained by curing the (meth) acrylic resin composition is further improved in various physical properties such as weather resistance, transparency, surface gloss, appearance, safety and the like. Can be done.

The amount of the (meth) acrylate used is
The range is preferably 99 to 50% by weight, more preferably 95 to 60% by weight, and still more preferably 90 to 70% by weight, based on 100% by weight of the whole vinyl monomer.

The amount of styrene, which is an essential component of the other vinyl monomer, is preferably in the range of 1 to 50% by weight.
More preferably 5 to 40% by weight, further preferably 10
３０30% by weight.

The above-mentioned vinyl monomer component may contain other vinyl compounds (monomers), if necessary, for example, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and vinylbenzoic acid; Unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid; monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, mono fumarate Monoesters of unsaturated dicarboxylic acids such as octyl and monoethyl citraconic acid; long-chain monomers having a carboxyl group obtained by esterifying the hydroxyl group of a (meth) acrylate ester having a hydroxyl group with an acid anhydride Allyl glycidyl ether; glycidyl (Meth) acrylate, methyl glycidyl (meth) acrylate; unsaturated epoxy compounds such as epoxy resin mono (meth) acrylate; polyisocyanates such as isocyanate ethyl methacrylate, tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate; Reaction product with a monomer having the formula: unsaturated isocyanate compound such as m-isopropenyl-α, α-dimethylbenzyl isocyanate; styrene-based monomer such as α-methylstyrene, vinyltoluene, chlorostyrene; vinyl acetate (Meth) acrylamide; (meth) acrylonitrile; N-alkoxy substitution such as N-methoxymethylacrylamide, N-ethoxymethylacrylamide, etc. Meth)
Acrylamide; unsaturated basic monomers such as aminoethylacrylamide; maleimide monomers such as N-phenylmaleimide, N-cyclohexylmaleimide, N-isopropylmaleimide; divinylbenzene, diallyl phthalate, diallyl isophthalate, triallylcia Examples include polyfunctional vinyl compounds such as nurate and triallyl isocyanurate, but are not particularly limited thereto. These vinyl compounds may be used alone or in combination of two or more.

The amount of the polyfunctional (meth) acrylic acid ester and the polyfunctional vinyl compound to be used may be determined according to the type thereof, the combination with the acrylic acid ester, etc., the use of the resin material and the desired physical properties. Although not particularly limited, it is preferably 0 to 20% by weight, more preferably 1 to 15% by weight, and still more preferably 2 to 10% by weight based on 100% by weight of the whole vinyl monomer. .

Next, the (meth) acrylic polymer used in the present invention will be described. The (meth) acrylic polymer is not particularly limited as long as it is a polymer of a monomer component containing (meth) acrylic acid and its ester as a main component, but a polymer having a carboxyl group or a hydroxyl group is preferable. . To obtain excellent strength and heat resistance of the cured product without causing phase separation of the cured product, a (meth) acrylic polymer having a polymerizable double bond in a side chain is desirable.

As the (meth) acrylic acid ester, those exemplified above can be used here. Among the above exemplified compounds, methyl methacrylate and a (meth) acrylate ester containing methyl methacrylate as a main component are particularly preferable. By using methyl methacrylate as the main component, the cured product obtained by curing the (meth) acrylic resin composition is further improved in various physical properties such as weather resistance, transparency, surface gloss, appearance, safety and the like. Can be done.

The amount of the monomer having a carboxyl group used is in the range of 0.5% to 20% by weight based on 100% by weight of the total of the (meth) acrylate and the monomer having a carboxyl group. And more preferably in the range of 1% by weight to 15% by weight.
More preferably, it is in the range of 10% by weight to 10% by weight. If the proportion of the monomer having a carboxyl group is less than 0.5% by weight, it is not preferable because physical properties such as heat resistance of the obtained cured product may be reduced. On the other hand, when the proportion of the monomer having a carboxyl group exceeds 20% by weight, the obtained cured product may have reduced weather resistance and water resistance.

The proportion of the monomer having a hydroxyl group in the monomer component is determined as follows.
Assuming that the total of the acrylate ester and the monomer having a hydroxyl group is 100% by weight, it is preferably in the range of 0.5% by weight to 20% by weight, and more preferably in the range of 1% by weight to 15% by weight. More preferably, 3% by weight to 10%
More preferably, it is within the range of weight%. If the proportion of the monomer having a hydroxyl group is less than 0.5% by weight, it is not preferable because physical properties such as heat resistance of the obtained cured product may be reduced. On the other hand, when the proportion of the monomer having a hydroxyl group exceeds 20% by weight, the weather resistance and water resistance of the obtained cured product may be reduced.

The above-mentioned monomer component may contain another vinyl compound (monomer) if necessary. The vinyl compound may be any compound having a polymerizable double bond, such as styrene, which is essential as a vinyl monomer component, and other vinyl compounds used as necessary as a vinyl monomer component. However, the present invention is not particularly limited to these. These vinyl compounds may be used alone or in combination of two or more.

In the case where another vinyl compound is mixed with the (meth) acrylic acid ester, the mixing ratio of the two, that is,
The content of the vinyl compound in the monomer component depends on the type of the vinyl compound, the combination with the (meth) acrylate, and the like, but is preferably 50% by weight or less.

When polymerizing the above monomer components, it is desirable to use a polymerization initiator. There is no particular limitation on the polymerization initiator, for example, benzoyl peroxide,
Organic peroxides such as lauroyl peroxide and methyl ethyl ketone peroxide; 2,2′-azobisisobutyronitrile, 2-phenylazo-2,4-dimethyl-
Examples include azo compounds such as 4-methoxyvaleronitrile, but are not particularly limited. These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator to be added to the monomer component is not particularly limited.

When polymerizing the above monomer components, it is more preferable to add a chain transfer agent in order to adjust the average molecular weight of the polymer. Such a chain transfer agent is not particularly limited, but a thiol compound, α-methylstyrene dimer, carbon tetrachloride, or the like is preferably used because the polymerization reaction of the monomer component is extremely easily controlled.
Examples of the thiol compound include alkyl mercaptans such as t-butyl mercaptan, n-octyl mercaptan, and n-dodecyl mercaptan; aromatic mercaptans such as thiophenol and thionaphthol; thioglycolic acid; octyl thioglycolate; Thioglycolic acid alkyl esters such as ethylene glycol dithioglycolate, trimethylolpropane tris- (thioglycolate) and pentaerythritol tetrakis- (thioglycolate); β-mercaptopropionic acid; β-
Octyl mercaptopropionate, 1,4-butanediol di (β-thiopropionate), trimethylolpropane tris- (β-thiopropionate), pentaerythritol tetrakis- (β-thiopropionate)
And the like, but are not particularly limited. One of these chain transfer agents may be used alone, or two or more thereof may be appropriately mixed and used.

The amount of the chain transfer agent to be used may be selected according to the type of the chain transfer agent, the combination with the (meth) allylic acid ester and the like, and is not particularly limited. Is preferably in the range of 0.1% by weight to 15% by weight, but is not particularly limited.

The polymerization method of the monomer component is not particularly limited, and examples thereof include known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Particularly preferred. The reaction conditions such as the reaction temperature and the reaction time for performing the above polymerization are not particularly limited, and for example, known reaction conditions can be adopted. Note that the polymerization is preferably performed in a nitrogen atmosphere. In particular, a method in which the polymerization of the monomer component is stopped halfway, that is, a partial polymerization is preferable.

As described above, a reaction mixture containing a polymer having a carboxyl group and a hydroxyl group is obtained. The weight average molecular weight (M
It is particularly preferable that w) is about 6,000 to 1,000,000 and the number average molecular weight (Mn) is about 3,000 to 500,000.

In order to introduce a polymerizable double bond into the side chain of the polymer, a method in which an unsaturated epoxy compound is reacted with a (meth) acrylic polymer having a carboxyl group in the side chain, or a method in which a hydroxyl is added to the side chain. A method of reacting a (meth) acrylic polymer having a group with an unsaturated isocyanate compound or an unsaturated acid anhydride is exemplified.

The unsaturated epoxy compound for introducing a polymerizable double bond into the side chain of the polymer is a compound having an epoxy group capable of reacting with a carboxyl group and a polymerizable double bond. Good. Specific examples of the unsaturated epoxy compound include allyl glycidyl ether; glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate; and mono (meth) acrylate of epoxy resin. These compounds may be used alone or in a combination of two or more.

The amount of the unsaturated epoxy compound to be used may be determined according to the combination with the polymer having a carboxyl group, and is not particularly limited. It is preferably in the range of 0.5 to 2 moles, more preferably in the range of 0.8 to 1.5 moles with respect to the monomer having a carboxyl group.

The (meth) acrylic polymer having a carboxyl group in the side chain is a monomer having a carboxyl group.
0.5% by weight based on 100% by weight of the total of the (meth) acrylate and the monomer having a carboxyl group.
The content is preferably in the range of 20% by weight, more preferably in the range of 1% to 15% by weight, and more preferably 3% by weight.
More preferably, it is in the range of 10% by weight to 10% by weight. When the proportion of the monomer having a carboxyl group is less than 0.5% by weight, the polymer can be introduced by reacting an unsaturated epoxy compound with a polymer obtained by polymerizing the monomer component. The number of sex double bonds is limited.
On the other hand, the ratio of the monomer having a carboxyl group is 20% by weight.
When it exceeds, the weather resistance and water resistance of the obtained cured product may be reduced.

In carrying out the esterification reaction, a general-purpose esterification catalyst can be added. When the esterification reaction is performed, a polymerization inhibitor may coexist.

As described above, a (meth) acrylic polymer in which the side chain having a polymerizable double bond is bonded to the main chain via an ester bond is obtained.

As a method of introducing a polymerizable double bond into an (meth) acrylic polymer via an ester bond, a method in which a carboxyl group is added to the epoxy group of a (meth) acrylic polymer having an epoxy group. May be reacted with a monomer having the formula:

As the unsaturated isocyanate compound, an isocyanate group capable of reacting with a hydroxyl group,
Any compound having a polymerizable double bond may be used. As the unsaturated isocyanate compound, specifically, a reaction product of a polyvalent isocyanate such as isocyanate ethyl methacrylate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the monomer having a hydroxyl group, m -Isopropenyl-α, α-dimethylbenzyl isocyanate. These compounds may be used alone or in a combination of two or more.

The amount of the unsaturated isocyanate compound to be used may be determined according to the combination with the polymer having a hydroxyl group, and is not particularly limited. It is preferably in the range of 0.5 to 2 moles, more preferably in the range of 0.8 to 1.6 moles with respect to the monomer having a hydroxyl group. The above-mentioned solvent, polymerization inhibitor and the like can also be used when performing the above urethane-forming reaction.

The (meth) acrylic polymer having a hydroxyl group in the side chain is obtained by converting a monomer having a hydroxyl group into
0.5% by weight based on 100% by weight of the total of the (meth) acrylate and the monomer having a hydroxyl group.
The content is preferably within the range of 20% by weight, from 1% by weight to
It is more preferably in the range of 15% by weight, and even more preferably in the range of 3% by weight to 10% by weight.
When the proportion of the monomer having a hydroxyl group is less than 0.5% by weight, the polymerization can be introduced by reacting an unsaturated isocyanate compound with a weight obtained by polymerizing the monomer component. The number of sex double bonds is limited. On the other hand, the ratio of the monomer having a hydroxyl group is 20
If the amount exceeds 10% by weight, the weather resistance and water resistance of the obtained cured product may be reduced.

When the urethanization reaction is performed, a urethanization catalyst can be added in order to allow the urethanization reaction to proceed efficiently. The urethanization catalyst is not particularly limited as long as it can promote the urethanization reaction, but dibutyltin dilaurate is preferred. One of these urethane-forming catalysts may be used alone, or two or more of them may be appropriately mixed and used.

The unsaturated acid anhydride may be any acid anhydride capable of reacting with a hydroxyl group and having a polymerizable double bond. Specific examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. These compounds may be used alone or in a combination of two or more.

Ratio of (meth) acrylic polymer to vinyl monomer in (meth) acrylic syrup (ratio)
Is preferably in the range of 5% by weight to 90% by weight, more preferably 7% by weight to 80% by weight, and still more preferably 10% by weight, with the total amount of both being 100% by weight. ７０70% by weight. The vinyl monomer content is preferably in the range of 95% by weight to 10% by weight, more preferably 93% by weight to 20% by weight, and still more preferably 9% by weight.
0% to 30% by weight.

The amount of the aluminum hydroxide used in the (meth) acrylic syrup depends on its type, combination with the (meth) acrylic syrup, etc., the use of the molding material, and the physical properties required for the molding material. The amount may be determined and is not particularly limited, but a range of 30 to 600 parts by weight with respect to 100 parts by weight of (meth) acrylic syrup is preferable. When the molding material is used as a sheet molding compound (SMC), 3 parts per 100 parts by weight of the (meth) acrylic syrup is used.
When it is used as a bulk molding compound (BMC) from 0 parts by weight to 300 parts by weight, the range is preferably from 150 parts by weight to 600 parts by weight. When used as a casting material, the amount is preferably in the range of 30 parts by weight to 350 parts by weight.

In the (meth) acrylic molding material of the present invention, if necessary, a thickener, a succinic acid derivative, a reinforcing material, a low-shrinking agent, a release agent, a coloring agent may be used as long as the effects of the present invention are not impaired. An agent may be added.

The thickener is not particularly limited and includes, for example, alkaline earth metal oxides such as magnesium oxide and calcium oxide; and alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide. One or more of these thickeners can be used. The amount of the thickener used depends on the type and use of the molding material, but is preferably 5 parts by weight or less based on 100 parts by weight of the (meth) acrylic syrup. By using the compound in an amount of 5 parts by weight or less, the viscosity of the compound after thickening can be set to a range suitable for a molding operation or the like. If the amount used exceeds 5 parts by weight, the viscosity of the compound after thickening becomes too high, and the working efficiency such as the molding operation is reduced, and the weather resistance and water resistance of the obtained molded product may be reduced. .

The succinic acid derivative has a function of suppressing the excessive thickening behavior by the thickener, particularly the initial thickening behavior. As the succinic derivative, a succinic acid skeleton or a succinic anhydride skeleton is provided in the molecule, and the ethylene group of the skeleton is substituted with an alkyl group, an alkenyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or the like. Any compound having a group may be used, and is not particularly limited, but a compound having 8 to 30 carbon atoms is preferable. A succin derivative having a total carbon number of 7 or less has poor solubility in a (meth) acrylic resin composition, especially in a (meth) acrylic syrup.
On the other hand, the succin derivatives having 31 or more carbon atoms have poor functions and effects expected by using the succin derivatives. That is, the effect of suppressing the excessive thickening behavior by the thickener is low.

Specific examples of the succinic derivatives include hexylsuccinic acid, heptylsuccinic acid, octylsuccinic acid, nonylsuccinic acid, decylsuccinic acid, dodecylsuccinic acid, tetradecylsuccinic acid, pentadecylsuccinic acid, hexadecylsuccinic acid, and heptasuccinic acid. Compounds having an alkyl group having 4 or more carbon atoms, such as decylsuccinic acid, octadecylsuccinic acid, pentadodecylsuccinic acid, and eicosylsuccinic acid; hexenylsuccinic acid, heptenylsuccinic acid, octenylsuccinic acid, nonenylsuccinic acid, decenylsuccinic acid, dodecenylsuccinic acid, Such as tetradecenyl succinic acid, pentadecenyl succinic acid, hexadecenyl succinic acid, heptadecenyl succinic acid, octadecenyl succinic acid, pentadodecenyl succinic acid, eicosenyl succinic acid, etc. A compound having an alkenyl group; B dodecyl succinic acid, a compound having an alicyclic hydrocarbon group such as cyclopropyl-dodecenyl succinic acid;
Compounds having an aromatic hydrocarbon group such as diphenylbutenylsuccinic acid; and anhydrides of these succinic acids, but are not particularly limited. These succinic acid derivatives may be used alone, or two or more of them may be appropriately mixed and used. The method for preparing the succinic derivative is not particularly limited.

The amount of the succinic acid derivative used depends on the type, combination with the (meth) acrylic syrup and the thickener, the use of the (meth) acrylic resin composition, and the like. The range of 0.01 to 10 parts by weight relative to part by weight is preferred. If the amount of the succinic acid derivative is less than 0.01 parts by weight, the expected action and effect of using the succinic acid derivative will be poor. That is, the effect of suppressing the excessive thickening behavior by the thickener may be poor. If the amount of the succinic acid derivative is more than 10 parts by weight, the viscosity of the compound after the thickening does not reach a predetermined value suitable for molding work,
Or it may take a long time to reach.

Examples of the reinforcing material include inorganic fibers such as glass fiber, carbon fiber, metal fiber, and ceramic fiber; and synthetic fibers such as aramid, polyester, and polyamide, and regenerated fibers, and organic fibers including natural fibers. These can be used alone or in combination of two or more. As the fiber form, for example, roving, chopped strand, mat, cloth (woven fabric, knitted fabric) and the like can be used.

The amount of the reinforcing material to be used may be determined according to its type, combination with syrup, etc., the use of the molding material and desired physical properties, and is not particularly limited. 2% to 40% by weight based on weight
Is preferably within the range. When the molding material is a sheet molding compound (SMC), the amount of the fiber reinforcing material used is more preferably in the range of 10% by weight to 40% by weight based on the total weight of the molding material. When the molding material is a bulk molding compound (BMC), the use amount of the fiber reinforcement is more preferably in the range of 2% by weight to 30% by weight based on the total weight of the molding material. By using the fiber reinforcing material within the above range, a molding material having excellent strength and elastic modulus when the molding material is formed into a molded product can be obtained.

As a low-shrinking agent, polymethyl methacrylate, polyethylene, polypropylene, polystyrene, polyethylene glycol, polypropylene glycol, cellulose butyrate, acetate, polyvinyl chloride, polyvinyl acetate, polycaprolactam, saturated polyester, or a copolymer thereof, A high degree of dimensional accuracy can be achieved by blending these in an appropriate amount.

The amount of the low-shrinkage agent may be determined according to the type, combination with (meth) acrylic syrup, etc., the use of the molding material and the desired physical properties, and is not particularly limited. However, the amount is preferably in the range of 5 to 50 parts by weight based on 100 parts by weight of the (meth) acrylic syrup.

The release agent is not particularly limited, and examples thereof include stearic acid, zinc stearate, aluminum stearate, calcium stearate, barium stearate, stearic acid amide, alkyl phosphate, and silicone oil. By mixing the agent, the mold can be easily separated from the mold.

The colorant is not particularly limited, and a known colorant such as an inorganic pigment or an organic pigment can be used.

The (meth) acrylic molding material of the present invention comprises:
It is particularly suitable as a molding material such as SMC, BMC, and casting material, and can be used in both casting and press molding methods. Kitchen counters, vanities, bathtubs, tables, wall materials It is molded into various forms such as floor materials, furniture, interior accessories, and seals, and is used for various purposes.

The mold to be used may be made of any material, as long as it is made of iron, aluminum, resin or the like.

[0058]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In the examples, "part" and "%"
Unless otherwise specified, “parts by weight” and “% by weight” are used, respectively.
Shall be expressed.

Example 1 In a reactor equipped with a thermometer, a cooler, a nitrogen gas inlet tube and a stirrer, 77 parts of methyl methacrylate (MMA) as a (meth) acrylate ester and 77 parts of a carboxyl group-containing monomer were added. After charging 3 parts of methacrylic acid (MAA) and 20 parts of styrene (SM), the inside of the reactor was purged with nitrogen gas. Next, the mixture was heated to 90 ° C. while stirring, and then 0.04 parts of 2,2′-azobisisobutyronitrile (AIBN) as a polymerization initiator and n-dodecyl mercaptan as a chain transfer agent 0.55 parts was added and a copolymerization reaction was carried out for 6 hours to obtain a methacrylic syrup containing an MMA / SM / MAA copolymer as a (meth) acrylic polymer. The weight average molecular weight of this methacrylic syrup measured using gel permeation chromatography (GPC) was 65,000. The solid content was 40%.

To 100 parts of this methacrylic syrup, 250 parts of aluminum hydroxide having a whiteness of 96 and an average particle diameter of 8 microns, and the obtained methacrylic syrup was a silane coupling agent (“A-174” manufactured by Nippon Unicar) 2 .5
Part, pentadodecenyl succinic acid 0.5 part as a succinic acid derivative, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane (manufactured by NOF Corporation) 1 part of perhexaTMH), 0.5 part of magnesium oxide as a thickener, 1 part of zinc stearate as an internal mold release agent, and 1 mm long glass fiber ("RES010-" manufactured by Nippon Sheet Glass Fiber Co., Ltd.) as a fiber reinforcing agent. BM
53 ") 27 parts were kneaded using a double-arm kneader for 30 minutes. Thereafter, the obtained material was placed in a closed container and aged at 40 ° C. for 24 hours to obtain a material with good stickiness and good handleability.

Using a mold having a cavity of 300 mm × 300 mm, the mold temperature of the upper mold was set to 120
℃, the mold temperature of the lower mold is 110 ℃, the thickener 1,
The mold was filled with 700 g, the mold was clamped at a pressure of 6 MPa, and heated and pressed for 10 minutes to produce a molded plate having a thickness of 9 mm. The following evaluation was performed about this molded plate. Table 1 shows the results.

(Appearance) The molded article was visually evaluated for uneven gloss and the surface smoothness was evaluated with a tentacle.

(Heat discoloration resistance) 1) Iron test: The degree of discoloration of the molded article after leaving the iron set at 200 ° C. for 10 minutes was measured, and the difference in the degree of discoloration before and after the standing was calculated. did. 2) Oven test: The degree of discoloration after placing the molded article in an oven at 170 ° C. for one hour was measured, and the difference in the degree of discoloration before and after the oven test was calculated and used as an index of heat discoloration resistance. The degree of discoloration was measured using a color difference meter (“Sigma 90 System” manufactured by Nippon Denshoku Co., Ltd.).

(Evaluation of Stain Resistance) The contaminants listed below were left on the molded product for 24 hours, washed with water and a neutral detergent, and the appearance of the molded product, such as gloss and coloring, was visually evaluated. . Contaminants: soy sauce, sauce, food red, red ginger, whiskey, coffee, tea, tabasco, mustard, lipstick, hair dye, red ink, blue ink, crayon

Example 2 A molded plate was prepared and evaluated in the same manner as in Example 1, except that 97 parts of methacrylic syrup of Example 1 was used and 3 parts of trimethylolpropane trimethacrylate was used as a crosslinking agent. Table 1 shows the results.

Example 3 67 parts of the methacrylic syrup of Example 1 were used, and 3 parts of trimethylolpropane trimethacrylate were used as a crosslinking agent.
Polymethyl methacrylate (weight average molecular weight 60,00
A molded plate was prepared and evaluated in the same manner as in Example 1 except that 30 parts of 0) were used. Table 1 shows the results.

Example 4 77 parts of MMA, 3 parts of MAA and 20 parts of SM were placed in a reactor equipped with a thermometer, a cooler, a nitrogen gas inlet tube and a stirrer, and then the inside of the reactor was replaced with nitrogen gas. Next, the mixture was heated to 90 ° C. while stirring, and 0.2 parts of AIBN as a polymerization initiator and 0.5 parts of n-dodecyl mercaptan as a chain transfer agent were added, and a copolymerization reaction was performed for 5 hours. Was carried out to obtain a methacrylic syrup containing the MMA / SM / MAA copolymer. The weight average molecular weight of this methacryl syrup measured by GPC was 70,000. The solid content was 25%.

To 100 parts of this methacrylic syrup, 180 parts of aluminum hydroxide having a whiteness of 89 and an average particle size of 25 microns, 1.8 parts of a silane coupling agent ("A-174" manufactured by Nippon Unicar Co., Ltd.), a curing agent Screw-4 as
0.5 parts of t-butylcyclohexyl peroxydicarbonate (“Percadox 16” manufactured by Kayaku Akzo),
Defoaming agent ("BYK A-55" manufactured by BYK Japan KK)
5 ") 0.2 parts were mixed to prepare a raw material slurry for casting. After degassing the slurry under reduced pressure, the distance between each other is 8 mm.
Pour the periphery of two glass plates facing each other so as to form a cell sealed with a so-called elastic gasket,
For 1 hour and further at 120 ° C. for 2 hours to produce a flat plate having a thickness of 8 mm. The characteristics were evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 Instead of the aluminum hydroxide of Example 1, the whiteness was 9
8. The characteristics were evaluated in the same manner as in Example 1 except that aluminum hydroxide having an average particle size of 8 microns was used. Table 1 shows the results.

Comparative Example 2 A reactor equipped with a thermometer, a cooler, a nitrogen gas inlet tube and a stirrer was charged with 97 parts of MMA and 3 parts of MAA, and the inside of the reactor was replaced with nitrogen gas. Next, the mixture was heated to 90 ° C. while stirring, and then AIBN was used as a polymerization initiator.
0.04 part and 0.55 part of n-dodecyl mercaptan as a chain transfer agent were added and a copolymerization reaction was carried out for 5 hours to obtain a methacryl syrup containing an MMA / MAA copolymer. The weight average molecular weight of this methacryl syrup measured using GPC was 65,000. The solid content was 40%.

To 100 parts of this methacrylic syrup, 250 parts of aluminum hydroxide having a whiteness of 96 and an average particle diameter of 8 μm, 2.5 parts of a silane coupling agent (“A-174” manufactured by Nippon Unicar), succinic acid 0.5 parts of pentadodecenyl succinic acid as a derivative and 1, as a curing agent
1-bis- (t-hexylperoxy) -3,3,5 trimethylcyclohexane ("Perhexa T" manufactured by NOF Corporation
MH ") 1 part, magnesium oxide 0.5 as thickener
Parts, 1 part of zinc stearate as an internal release agent, and 27 parts of 1 mm-long glass fiber (“RES010-BM53” manufactured by Nippon Sheet Glass Fiber Co., Ltd.) as a fiber reinforcing agent were kneaded for 30 minutes using a double-arm kneader. . Thereafter, the obtained material was placed in a closed container and aged at 40 ° C. for 24 hours to obtain a material with no stickiness and good handleability.

Using a mold having a cavity of 300 mm × 300 mm, the upper mold temperature was set to 120
℃, the mold temperature of the lower mold is 110 ℃, the thickener 1,
The mold was filled with 700 g, the mold was clamped at a pressure of 6 MPa, and heated and pressed for 10 minutes to produce a molded plate having a thickness of 9 mm. When this molded plate was evaluated, blurring occurred on the surface of the molded product, and the surface smoothness became poor.

[0073]

[Table 1]

[0074]

According to the present invention, it is possible to obtain a (meth) acrylic molding material having a good appearance when formed into a molded product and having a small degree of thermal discoloration.

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Claims (3)

[Claims] 1. An aluminum hydroxide having a whiteness in the range of 80 to 97, a vinyl monomer containing (meth) acrylate and styrene as essential components, and a (meth) acrylic polymer as main components. A (meth) acrylic molding material characterized by being contained in a (meth) acrylic syrup. 2. An aluminum hydroxide having an average particle size of 3
The (meth) acrylic molding composition according to claim 1, wherein the composition has a size in the range of from 50 to 50 microns. 3. A molded article formed from the (meth) acrylic molding material according to claim 1.