JP3497907B2 - Methacrylic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a methacrylic resin composition. Since the methacrylic resin composition provided by the present invention is excellent in impact resistance, strain whitening resistance, transparency and mechanical properties, it is a vehicle part such as a front plate of a motorcycle or a mechanical part such as a front plate of a vending machine. It is useful as a material for building materials such as carports.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin is used in a wide range of fields such as automobile parts, electrical parts, industrial parts and sundries due to its excellent properties such as transparency, weather resistance and mechanical properties. On the other hand, it has drawbacks such as poor impact resistance, which is an obstacle to expansion of applications. Many proposals have been made for a method of imparting impact resistance to a methacrylic resin, but among them, a shell is prepared by graft-polymerizing a monomer mixture containing methyl methacrylate as a main component onto a core composed of rubber-like particles. A methacrylic resin composition in which the multilayer structure copolymer particles obtained by forming are dispersed in a methacrylic resin is excellent in impact strength, transparency and the like, and is widely used industrially (UK Patent 1, 340,02
5 and British Patent 1,414,187).

[0003]

However, when the above methacrylic resin composition is molded, it tends to be whitened when strained, and the excellent transparency originally possessed by the methacrylic resin tends to decrease. In order to mitigate this tendency, there is a method of reducing the particle size of the rubber-containing multi-layer structure copolymer, but if the particle size is reduced, the impact resistance of the obtained molded article decreases, so It is necessary to disperse a large amount of rubber-containing multi-layer structure copolymer, and even in a state where no strain is applied, not only the transparency is significantly lowered, but also the mechanical properties such as hardness and strength are lowered. there were. A method has also been proposed in which a multi-layer structure polymer in which a hard layer and a rubber layer are gradually changed is dispersed in a methacrylic resin (Japanese Patent Laid-Open No. 53-58554).
However, whitening due to distortion has not been significantly reduced. Thus, the object of the present invention is to provide impact resistance,
It is intended to provide a methacrylic resin composition having excellent strain whitening resistance, transparency and mechanical properties.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that rubber-containing multilayer structure copolymer particles and a non-crosslinking hard polymer having a crosslinkable hard polymer as an inner core. A methacrylic resin composition having excellent impact resistance, strain whitening resistance, transparency and mechanical properties can be obtained by simultaneously dispersing methacrylic multi-layered polymer particles having a coalesced shell as an outer shell in a methacrylic resin. The present invention has been completed and the present invention has been completed.

That is, according to the present invention, (A) 10 to 92% by weight of a methacrylic resin mainly containing a methyl methacrylate unit (hereinafter, this may be abbreviated as methacrylic resin A), (B) the following [a]: And / or (C) the multilayer structure copolymer defined by the following [B] (hereinafter referred to as "multilayer structure copolymer" (hereinafter, referred to as "multilayer structure copolymer B")) May be abbreviated as a multilayer structure copolymer C) 87 to 5% by weight, and (D) a methacrylic polymer defined by the following [C] (hereinafter abbreviated as a methacrylic polymer D). There is 3) to 50% by weight of the methacrylic resin composition. [A] (meth) acrylic acid alkyl ester having an alkyl group having 2 to 12 carbon atoms 69.9 to 94.9% by weight, styrene 30 to 5% by weight, and a polymerizable polyfunctional compound 0.1 to 5% by weight. % Monomer mixture or the following general formula (I)

[Chemical 3] (In the formula, R represents a hydrogen atom or a methyl group.) 25 to 75% by weight of a diene monomer and an alkyl acrylate ester having 2 to 8 carbon atoms 75 to 2
A monomer mixture consisting of 5% by weight is polymerized, and 100 parts by weight of the resulting polymer is added with methyl methacrylate 80 to 99.9.
% -Monomer mixture 10-200 consisting of 20-0.1% by weight of monomers copolymerizable with methyl methacrylate
A multilayer structure copolymer having an average particle size of 0.05 to 0.4 μm obtained by polymerizing parts by weight in the presence of a chain transfer agent. [B] 80 to 99.9% by weight of methyl methacrylate, 1 to 20% by weight of an alkyl acrylate whose alkyl group has 1 to 4 carbon atoms, and a polymerizable polyfunctional compound
A monomer mixture consisting of 1 to 3% by weight is polymerized, and 100 parts by weight of the resulting polymer has 2 to 12 carbon atoms in the alkyl group.
(Meth) acrylic acid alkyl ester of 69.9 to 94.
A monomer mixture consisting of 9% by weight, 30 to 5% by weight of styrene and 0.1 to 5% by weight of a polyfunctional polymerizable compound,
Or the following general formula (I)

[Chemical 4] (In the formula, R represents a hydrogen atom or a methyl group.) 25 to 75% by weight of a diene monomer and an alkyl acrylate ester having 2 to 8 carbon atoms 75 to 2
50 to 2000 parts by weight of a monomer mixture consisting of 5% by weight are polymerized, and 100 parts by weight of the resulting polymer are added with 80 to 99.9% by weight of methyl methacrylate and 20 to 20% of a monomer copolymerizable with methyl methacrylate. A multilayer structure copolymer having an average particle size of 0.05 to 0.5 μm obtained by polymerizing 10 to 100 parts by weight of a monomer mixture of 0.1% by weight in the presence of a chain transfer agent. [C] 50 to 95% by weight of methyl methacrylate, 1 to 20% by weight of an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms, and a polymerizable polyfunctional compound 4 to 4
A monomer mixture consisting of 0% by weight is polymerized, and 100 parts by weight of the obtained polymer is added with methyl methacrylate 80 to 99.5.
10-300 monomer mixture consisting of 20% to 0.5% by weight of monomers copolymerizable with methyl methacrylate
A methacrylic polymer having an average particle size of 0.01 to 0.4 μm obtained by polymerizing parts by weight in the presence of a chain transfer agent.

In the present invention, the methacrylic resin A is 1
It is necessary to blend 0 to 92% by weight. Methacrylic resin A
When the compounding amount is less than 10% by weight, the transparency and mechanical performance originally possessed by the methacrylic resin deteriorates, and when it exceeds 92% by weight, the impact resistance decreases. The multilayer structure copolymer B and / or the multilayer structure copolymer C is added in an amount of 87 to 5 in order to improve the impact resistance of the methacrylic resin composition.
It is necessary to blend by weight%. When the content is less than 5% by weight, impact resistance of the resulting methacrylic resin composition is impaired, and when it exceeds 87% by weight, mechanical properties such as high hardness and elastic modulus originally possessed by the methacrylic resin are impaired. Further, it is preferable to use the multilayer structure copolymer B for applications requiring more strain whitening resistance, and it is preferable to use the multilayer structure copolymer C for applications requiring more impact resistance. The blending amount of the methacrylic polymer D in the present invention is required to be within the range of 3 to 50% by weight, preferably within the range of 5 to 30% by weight. The blending amount is
If it is less than 3% by weight, the strain-whitening resistance of the methacrylic resin composition is impaired, and if it exceeds 50% by weight, the impact resistance of the methacrylic resin composition is impaired.

In the methacrylic resin A of the present invention, the content of methyl methacrylate units is preferably 80% by weight or more, and the content of structural units derived from other monomers copolymerizable with methyl methacrylate is 20. It is preferably not more than weight%. As the monomer, styrene;
Acrylonitrile; alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate;
Alkyl group having 2 to 8 carbon atoms such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and octyl methacrylate; alkyl methacrylate; cyclohexyl methacrylate, adamantyl methacrylate, isobornyl methacrylate; Examples thereof include methacrylic acid esters having an alicyclic skeleton or an aromatic ring skeleton such as phenyl methacrylate, and these may be used alone or in combination of two or more kinds.

The multilayer structure copolymer B in the present invention has a substantially two-layer core-shell structure comprising an inner core made of a crosslinked rubber component and an outer shell made of a hard component. The substantially two-layer core-shell structure referred to here is
Not only the two-layer core-shell structure in which the inner core and the outer shell are distinguished by a clear boundary, but around the boundary, the polymer components of the inner core and the polymer components of the outer shell are mixed and the boundary becomes slightly unclear. It also includes a core-shell structure that has a core-shell structure and a core-shell structure in which a part of the outer shell component has entered the inner core.

The inner core is a (meth) acrylic acid alkyl ester having an alkyl group of 2 to 12 carbon atoms 69.9 to 94.9.
It is obtained by polymerizing a monomer mixture (hereinafter, may be abbreviated as mixture A) consisting of 30 wt% of styrene, 30-5 wt% of styrene, and 0.1-5 wt% of a polymerizable polyfunctional compound. Polymer or 25 to 75% by weight of the diene monomer represented by the above general formula (I) and an alkyl acrylate ester having 25 to 8 carbon atoms in the alkyl group 75 to 25
It is composed of a polymer obtained by polymerizing a monomer mixture (hereinafter, may be abbreviated as mixture B) composed of wt%.

The carbon number of the alkyl group in mixture A is 2
As the (meth) acrylic acid alkyl ester of to 12, for example, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth)
Examples thereof include 2-ethylhexyl acrylate, octyl (meth) acrylate, decyl methacrylate, dodecyl methacrylate, and the like, of which butyl acrylate is preferable.
The compounding ratio of the (meth) acrylic acid alkyl ester is 9
When it exceeds 4.9% by weight, the transparency of the obtained methacrylic resin composition decreases, and when it is less than 69.9% by weight, impact resistance and transparency decrease. The compounding ratio of styrene is within the range of 30 to 5% by weight. When it is out of this range, the transparency of the obtained methacrylic resin composition is significantly lowered. The polymerizable polyfunctional compound is a monomer having two or more carbon-carbon double bonds in the molecule, and a group consisting of allyl alcohol and / or methallyl alcohol, acrylic acid, methacrylic acid, and cinnamic acid. Preferred is an ester with at least one acid selected from the group consisting of diesters with at least one acid component selected from the group consisting of phthalic acid, terephthalic acid and isophthalic acid. Specific examples include allyl acrylate, methallyl acrylate, allyl methacrylate, methallyl methacrylate, allyl cinnamate, methallyl cinnamate, diallyl phthalate, diallyl terephthalate and diallyl isophthalate. These may be used alone or in combination of two or more. Since the polyfunctional compound functions as a grafting agent for adhering the outer shell and the inner core by a chemical bond in the polymerization reaction for forming the outer shell, when the compounding ratio is less than 0.1% by weight, the inner core and the outer shell are The adhesiveness between
When it exceeds 5% by weight, the performance as a rubber is deteriorated due to a crosslinking reaction which proceeds at the same time as the graft reaction.
The impact resistance of the obtained methacrylic resin composition decreases.

Mixture A can also contain other monomers copolymerizable with the above components. Examples of the monomer include α-methylstyrene, p-methylstyrene, methyl cinnamate, acrylonitrile and the like, and the content thereof is preferably 10% by weight or less. If it exceeds 10% by weight, the transparency and mechanical performance originally possessed by the methacrylic resin may be impaired.

The carbon number of the alkyl group in the mixture B is 2
As the acrylic acid alkyl ester of ~ 8, for example,
Examples thereof include ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate. Among them, butyl acrylate is preferable from the viewpoint of impact resistance. The diene monomer represented by the general formula (I) is butadiene and isoprene, and these may be used alone or in combination of both. The weight ratio of the diene monomer and the alkyl acrylate is required to be in the range of 25:75 to 75:25 in the former ratio to the latter ratio. If the ratio is out of this range, the resulting methacrylic resin composition will be obtained. The transparency of the product is significantly reduced.

It is also possible to add a polyfunctional compound capable of being polymerized to the mixture B in an amount of 5% by weight or less.
Other copolymerizable monomers may be blended as long as the content is at most wt%. Examples of the polyfunctional compound include those similar to those used in the mixture A, and other copolymerizable monomers include butyl methacrylate, 2-ethylhexyl methacrylate, and the like. 4 to 12 alkyl methacrylate, α-methylstyrene, p-methylstyrene, methyl cinnamate, acrylonitrile and the like. If the compounding amount of the polyfunctional compound exceeds 5% by weight, the performance as a rubber is deteriorated, the impact resistance of the obtained methacrylic resin composition is deteriorated, and the compounding amount of other copolymerizable monomer is decreased. If it exceeds 20% by weight, the transparency and mechanical performance originally possessed by the methacrylic resin may be impaired.

The outer shell is a monomer comprising 80 to 99.9% by weight of methyl methacrylate and 20 to 0.1% by weight of a monomer copolymerizable with methyl methacrylate in the above polymer forming the inner core. It is formed by polymerizing a mixture (hereinafter sometimes abbreviated as mixture C) in the presence of a chain transfer agent. Examples of the monomer copolymerizable with methyl methacrylate are the same as those used in the methacrylic resin A. The chain transfer agent is necessary for controlling the molecular weight of the polymer forming the outer shell and ensuring the fluidity of the particles, and it is an alkyl mercaptan such as octyl mercaptan or lauryl mercaptan that is usually used in radical polymerization; thioglycolic acid. Examples thereof include thioglycolic acid alkyl esters such as thioglycolic acid methyl ester; and aromatic mercaptans such as thiophenol.
Among them, octyl mercaptan and lauryl mercaptan are preferably used. The weight ratio of methyl methacrylate to the other monomer copolymerizable with methyl methacrylate is in the range of 80:20 to 99.9: 0.1 in the ratio of the former to the latter. When the amount of methyl methacrylate is less than this range, the compatibility between the multilayer structure copolymer B and the matrix composed of the methacrylic resin is lowered, and the dispersibility of the particles in the matrix is deteriorated. The transparency of the composition is reduced. On the other hand, when the amount of methyl methacrylate exceeds the above range, the thermal decomposition resistance and molding processability of the obtained methacrylic resin composition deteriorate.

The weight ratio of the mixture C or the polymer obtained by polymerizing the mixture A or the mixture B used in the production of the multilayer structure copolymer B to the mixture C is 10: 1 to 10:20.
Within the range of. When the amount of the mixture C is more than the range, the impact resistance of the obtained methacrylic resin composition is lowered, and when the amount is less than the range, the dispersibility of the particles in the matrix is lowered, and thus it is obtained. Moldability of the methacrylic resin composition decreases.

The average particle size of the multi-layer structure copolymer B is 0.0
It is necessary to be in the range of 5 to 0.4 μm, and if it is out of this range, the impact resistance strength of the obtained methacrylic resin composition is lowered. As the multilayer structure copolymer B, the multilayer structure copolymer obtained from the mixture A or the multilayer structure copolymer obtained from the mixture B may be used alone or in combination.

The multilayer structure copolymer C in the present invention comprises a polymer forming a first layer comprising a crosslinked hard component, a polymer forming a second layer comprising a crosslinked rubber component and a hard component. Consisting of a polymer forming the third layer,
It has a substantially three-layer core-shell structure. The three-layer core-shell structure here means that a second layer, which is an intermediate shell, is formed outside the inner core made of the first layer, and a third layer, which is an outer shell, is formed outside the second layer. The core-shell structure of the first layer and the second layer is substantially the same as the core-shell structure of substantially two layers described above. A core-shell structure in which the boundary between the second layer and the third layer is somewhat unclear, a core-shell structure in which some of the components of the second layer are in the first layer, and one of the components of the third layer It also includes a core / shell structure in which a part is included in the second layer and / or the first layer.

The first layer is made of methyl methacrylate 80-9.
A monomer mixture consisting of 9.9% by weight, 1 to 20% by weight of an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms, and 0.1 to 3% by weight of a polymerizable polyfunctional compound (hereinafter referred to as a mixture). (Sometimes abbreviated as D). In the mixture D, when the amount of methyl methacrylate is less than 80% by weight, the transparency of the obtained methacrylic resin composition decreases. In order to improve the thermal decomposition resistance of the methacrylic resin composition, the alkyl acrylate whose alkyl group has 1 to 4 carbon atoms is 1 to 2 carbon atoms.
0 wt% is required. The polymerizable polyfunctional compound also functions as a grafting agent in the polymerization reaction forming the second layer, and in order to improve the adhesiveness between the first layer and the second layer,
The amount is required to be 0.1% by weight or more, but if the amount is too large, the transparency and thermal decomposition resistance of the obtained methacrylic resin composition decrease, so the upper limit is 3% by weight.

The second layer of the multi-layer structure copolymer C is formed by polymerizing the mixture A or the mixture B with the polymer forming the first layer, so that the polymer forming the first layer is the core. A polymer having a substantially two-layer core-shell structure in which the second layer forms the outer shell on the outside thereof is obtained.

A mixture C was added to the polymer thus obtained.
Is polymerized in the presence of a chain transfer agent to form a third layer, resulting in a multi-layer structure copolymer C. The reaction conditions are the same as those for forming the second layer of the multilayer structure copolymer B.

In the production of the multi-layer structure copolymer C, the weight ratio of the mixture A or the mixture B and the polymer for polymerizing it is 50: 100 to 2000: 10 in the ratio of the former to the latter.
It is in the range of 0, and the weight ratio of the mixture C to the polymer for polymerizing the mixture is in the range of 10: 100 to 100: 100 in the former ratio to the latter ratio. If the amount is out of these ranges, impact resistance and transparency of the obtained methacrylic resin composition deteriorate. In the multilayer structure copolymer C, the proportion of the polymer forming the second layer is preferably within the range of 30 to 80% by weight, more preferably within the range of 35 to 60% by weight. The average particle size of the multi-layer structure copolymer C needs to be in the range of 0.05 to 0.5 μm, and if it is out of this range, the impact resistance strength of the methacrylic resin composition is significantly reduced.

The methacrylic polymer D in the present invention is
A particle having a substantially two-layer core-shell structure formed by an inner core made of a hard crosslinkable polymer and an outer shell made of a non-crosslinkable polymer, which is strain whitening resistance and mechanical properties of a methacrylic resin composition. It is necessary to improve the physical properties. The inner core is composed of 50 to 95% by weight of methyl methacrylate, 1 to 20% by weight of an alkyl acrylate whose alkyl group has 1 to 4 carbon atoms, and a polymerizable polyfunctional compound 4 to 4%.
It is composed of a polymer obtained by polymerizing a monomer mixture consisting of 40% by weight (hereinafter, this may be abbreviated as mixture E).

The polymerizable polyfunctional compound in the mixture E is a compound having two or more carbon-carbon double bonds in the molecule, such as ethylene glycol methacrylic acid diester and 1,3-butylene glycol methacrylic acid diester. , Hexamethylene glycol methacrylic acid diester, ethylene glycol acrylic acid diester, hexamethylene glycol acrylic acid diester, trimethylolpropane methacrylic acid triester, allyl acrylate, allyl methacrylate, allyl cinnamate, methallyl cinnamate, diallyl phthalate, terephthalate Examples thereof include diallyl acid diallyl, diallyl isophthalate, triallyl cyanurate or divinylbenzene. Among them, all carbon-carbon double bonds exhibit good copolymerizability with methyl methacrylate, that is, the carbon Compounds between double bond monomer reactivity ratios (r2) satisfies the formula (II) below are preferred. 0.1 ≦ r1 × r2 ≦ 2.0 (II) (where, r1 is the monomer reactivity ratio of methyl methacrylate,
r2 represents the monomer reactivity ratio of the carbon-carbon double bond of the polymerizable polyfunctional compound. ) If the value of r1 × r2 (product of monomer reactivity ratio) is out of this range, the degree of cross-linking becomes low, and the strain-whitening resistance tends to decrease. The polymerizable polyfunctional compound satisfying the formula (II) is preferably a diester or triester of (meth) acrylic acid and a diol or triol, specifically, ethylene glycol methacrylic acid diester, Examples thereof include 1,3-butylene glycol methacrylic acid diester, trimethylolpropane methacrylic acid diester, ethylene glycol acrylic acid diester, hexamethylene glycol methacrylic acid diester, and hexamethylene glycol acrylic acid diester.

When the amount of methyl methacrylate in the mixture E is less than 50% by weight, the transparency of the obtained methacrylic resin composition is lowered. In order to improve the thermal decomposition resistance of the methacrylic resin composition, the carbon number of the alkyl group is 1 to
It is necessary that the acrylic acid alkyl ester of 4 is blended in an amount of 1 to 20% by weight. When the amount of the polymerizable polyfunctional compound is less than 4% by weight, the strain-whitening resistance and mechanical performance of the obtained methacrylic resin composition are deteriorated, and 4
If it exceeds 0% by weight, the transparency decreases. If necessary, the mixture E may contain other copolymerizable monomer. Other copolymerizable monomers include methacrylic acid alkyl esters having an alkyl group having 2 to 8 carbon atoms such as styrene, acrylonitrile, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and methacrylic acid. Examples thereof include methacrylic acid esters having an alicyclic skeleton or an aromatic ring such as isobornyl acid and phenyl methacrylate, and these may be used alone or in combination.

The outer shell of the multi-layer structure copolymer C is formed in the same manner as the outer shell of the multi-layer structure copolymer B. The average particle size of the methacrylic polymer D needs to be in the range of 0.01 to 0.4 μm, and preferably in the range of 0.01 to 0.2 μm. When it exceeds 0.4 μm, the strain-whitening resistance of the methacrylic resin composition is lowered, and when it is less than 0.01 μm, the impact strength is lowered.

The polymerization method for producing the multi-layer structure copolymer B, the multi-layer structure copolymer C and the methacrylic polymer D in the present invention is not particularly limited, but a spherical multi-layer structure polymer can be easily obtained. The emulsion polymerization method is preferred. Hereinafter, the emulsion polymerization method will be described as an example. Put deionized water and an emulsifier in a reaction vessel, to carry out the polymerization by adding the components of the monomer mixture for producing a polymer forming an inner core,
Next, a polymerization reaction for forming an outer shell (second layer in the case of the multilayer structure copolymer C) is performed. In the case of the multi-layer structure copolymer C, a polymerization reaction for forming the third layer is further performed. The polymerization temperature is preferably in the temperature range of 10 to 120 ° C., 30 to 10
The range of 0 ° C is more preferable. The polymerization time varies depending on the type and amount of the polymerization initiator and the emulsifier, the polymerization temperature, etc., but is usually 3 for each polymerization reaction forming each layer.
It is within the range of 0 minutes to 7 hours. The weight ratio of the monomer mixture to water is preferably in the range of 5:95 to 70:30 in terms of the former ratio to the latter ratio. The total amount of the components of the monomer mixture may be charged at once or dividedly, but it is preferable to divide the components to efficiently remove the heat generated by the polymerization.

As the emulsifier, an anionic surfactant,
Nonionic surfactants, nonionic-anionic surfactants and the like usually used in emulsion polymerization are used, for example, sodium stearate, sodium oleate and the like long-chain alkylcarboxylic acid salts or long-chain alkenylcarboxylic acid Salt, alkyl sulfate such as sodium lauryl sulfate, sodium di (2-ethylhexyl) sulfosuccinate, sodium lauryl sarcosinate, polyoxyethylene nonylphenyl alcohol, polyoxyethylene dodecyl ether, sodium polyoxyethylene dodecyl ether sulfate, etc. Is mentioned. The polymerization initiator is not particularly limited, and usually used persulfates such as potassium peroxosulfate, inorganic initiators such as perborate salts such as sodium perborate, and combinations thereof with sulfites such as sodium sulfite. Redox initiators such as a combination of an organic hydroperoxide such as benzoyl peroxide and cumene hydroperoxide with a first metal salt such as ferrous sulfate and ferric chloride or a hydrate thereof, and the like. .

The particle size of the emulsion can be appropriately adjusted depending on the emulsification conditions such as the type and concentration of the emulsifier. The particle size is measured by a known method such as a microscope observation method, an absorbance method, a static light scattering method, a dynamic light scattering method, and a centrifugal sedimentation method in the state of latex at the end of the polymerization.

A polymer latex is obtained by the above emulsion polymerization. Next, this is solidified and dried according to a known method.

By mixing the thus obtained multi-layer structure copolymer B and / or multi-layer structure copolymer C and the methacrylic polymer D with the methacrylic resin A containing methyl methacrylate units as a main component, The methacrylic resin composition of the present invention can be obtained. As a method of mixing these, any method may be used as long as it can be uniformly mixed, and all commonly used resin mixing methods can be applied. For example, in the melt mixing method, prior to the melt mixing, in addition to the above resin components, if necessary, a stabilizer, a dye, a pigment,
V type blender, plasticizer, lubricant, filler, etc.
After mixing with a Henschel mixer or the like, the mixture is melt-kneaded at 150 to 300 ° C. using a mixing roll screw type extruder or the like. Further, a latex containing a multilayer structure copolymer B and / or a multilayer structure copolymer C and a methacrylic polymer D obtained by an emulsion polymerization method and a latex of a methacrylic resin A mainly containing a methyl methacrylate unit are blended. After that, a method of separating and taking out the resin is exemplified.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples. The physical properties of the obtained multilayer structure copolymer, methacrylic polymer and methacrylic resin composition were evaluated by the following methods. <Particle size> Light scattering particle size measuring device (P by Otsuka Electronics Co., Ltd.
It was measured using AR-III). <Impact resistance> A small test piece obtained by injection molding is conditioned (2
After 3 ° C., 60% RH, 24 hours), a notching machine (Mini-max manufactured by CSI Co.) was used to make a notch (tip radius 0.25 mm, depth 1.3 mm), and an Izod impact tester (CSI Co.) Made Mini-max Imp
The impact strength was measured by the Act Tester). <Distortion whitening property> A dumbbell-shaped test piece was prepared from a plate having a thickness of 0.2 mm, and the microphotometer (P1 manufactured by Nippon Kogaku Co., Ltd.)
Elongation and total light transmittance were measured at the same time using a tensile tester equipped with (Autograph AG5000 manufactured by Shimadzu Corporation, strain rate 0.1 mm / min), and the total light transmittance at 10% elongation was measured. evaluated. <Transparency> A dumbbell-shaped test piece is prepared from a plate having a thickness of 0.2 mm, and a microscopic photometer (P1 manufactured by Nippon Kogaku Co., Ltd.)
The total light transmittance was measured by using. <Elastic Modulus> A dumbbell-shaped test piece is prepared from a plate having a thickness of 1 mm, and a tensile tester (AG500 manufactured by Shimadzu Corporation) is used.
0, strain rate 2 mm / min).

Synthesis Example 1 (Synthesis of Multilayer Copolymer [B-1]) 600 g of distilled water and lauryl sarcosine as an emulsifier were placed in a 2 liter polymerization vessel equipped with a stirring blade, a cooling tube and a dropping funnel under a nitrogen atmosphere. Sodium acid salt (0.168 g) and sodium stearate (2.1 g) were added, and the mixture was heated to 70 ° C. and uniformly dissolved. Then, 124.05 g of butyl acrylate (hereinafter abbreviated as BA), 25.95 g of styrene (hereinafter abbreviated as St) and allyl methacrylate (hereinafter referred to as ALM) as a polymerizable polyfunctional compound.
After adding 0.15 g of abbreviated A) and stirring for 30 minutes, 0.15 g of potassium peroxodisulfate (hereinafter abbreviated as KPS) was added to initiate polymerization. After 4 hours, it was confirmed by gas chromatography (hereinafter, abbreviated as GC) that all the respective monomers were consumed. Next, after adding 0.3 g of KPS to the obtained copolymer latex, methyl methacrylate (hereinafter abbreviated as MMA) 144.
0 g, ethyl acrylate (hereinafter abbreviated as EA) 6.
A mixture of 0 g and 0.3 g of n-octyl mercaptan (hereinafter abbreviated as n-OSH) as a chain transfer agent was added dropwise from a dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes, and it was confirmed that each monomer was consumed, and then the polymerization was completed. The particle size of the obtained latex was 0.30 μm. This was cooled to −20 ° C. for 24 hours to aggregate, then the aggregate was taken out and washed with hot water at 80 ° C. three times. Furthermore, it is dried under reduced pressure at 80 ° C for 2 days,
A multilayer structure copolymer [B-1] was obtained. The results are shown in Table 1.

Synthesis Examples 2 to 4 (multilayer structure copolymer [B-
[2] to [B-4] Synthesis] In Synthesis Example 1, the same operation as in Synthesis Example 1 was performed except that the composition and the amount of the emulsifier and the monomer mixture were changed as shown in Table 1, and a multilayer structure was obtained. Structural copolymer [B-2] to [B
-4] was obtained. The results are shown in Table 1.

Synthesis Example 5 (Synthesis of Multilayer Copolymer [B-5]) 200 g of distilled water in an autoclave of 0.5 liter, 4.0 g of sodium oleate as an emulsifier, Rongalit (formaldehyde sodium sulfoxylate).
0.267 g, disodium ethylenediaminetetraacetic acid
013 g and ferrous sulfate heptahydrate 0.008 g were charged, and the temperature was raised to 50 ° C. while stirring and purging with nitrogen. Thirty
After 4 minutes, 41.6 g of BA and 38.4 g of butadiene were added, and this temperature was maintained for another 30 minutes. Then, 0.1 g of cumene hydroperoxide was added to initiate polymerization. Four
After time, it was confirmed by GC that all the respective monomers were consumed. Next, 204 g of the obtained copolymer latex (copolymer amount: 57.2 g) was transferred to a 2 liter polymerization vessel equipped with a stirring blade, a cooling tube and a dropping funnel under a nitrogen atmosphere, and 86 g of distilled water was added. In addition, the temperature was raised to 70 ° C. Furthermore, after adding KPS 0.1g, MMA54.9g, EA
A mixture of 2.3 g and n-OSH 0.23 g as a chain transfer agent was added dropwise from the dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes, and it was confirmed that each monomer was consumed, and then the polymerization was completed. The particle size of the obtained latex was 0.12 μm. This is -20 ℃ 24
After cooling for a while to agglomerate, the agglomerate is taken out and kept at 80 ° C.
Washed with hot water three times. Further, it was dried under reduced pressure at 80 ° C. for 2 days to obtain a multilayer structure copolymer [B-5]. The results are shown in Table 1.

[0035]

[Table 1]

Synthesis Example 6 (Synthesis of Multilayer Copolymer [C-6]) 600 g of distilled water and lauryl sarcosine as an emulsifier in a 2 liter polymerization vessel equipped with a stirring blade, a cooling tube and a dropping funnel under a nitrogen atmosphere. Sodium acid salt (0.192 g) and sodium stearate (2.4 g) were added, and the mixture was heated to 70 ° C. and uniformly dissolved. Next, MMA115.2g,
4.8 g of EA and A as the polymerizable polyfunctional compound
Add 0.24 g of LMA and stir for 30 minutes to obtain KPS 0.1
Polymerization was started by adding 5 g. After 2 hours, it was confirmed by GC that all the respective monomers were consumed. Next, 0.15 g of KPS was added to the obtained polymer latex, and BA9 was added.
A mixture of 7.3 g, St 20.4 g, and ALMA (2.35 g) as a polymerizable polyfunctional compound was added dropwise from the dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another hour, and it was confirmed by GC that all the respective monomers were consumed. 0.3 g of KPS was added to the obtained copolymer latex.
Then, a mixture of 62.0 g of MMA, 2.4 g of EA and 0.12 g of n-OSH as a chain transfer agent was added dropwise from the dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes, and it was confirmed by GC that each monomer was consumed, and the polymerization was completed. The particle size of the obtained latex is 0.2
It was 7 μm. This was cooled to −20 ° C. for 24 hours to aggregate, then the aggregate was taken out and washed with hot water at 80 ° C. three times. Further, it was dried under reduced pressure at 80 ° C. for 2 days to obtain a multilayer structure copolymer [C-6]. The results are shown in Table 2.

Synthesis Examples 7 to 9 (multilayer structure copolymer [C-
7] to [C-9] Synthesis Example 6 except that the composition and the amount of the emulsifier and the monomer mixture used in Synthesis Example 6 were changed as shown in Table 2.
The same operation as above is carried out, and the multilayer structure copolymer [C-7]
[C-9] was obtained. The results are shown in Table 2.

Synthesis Example 10 (Multilayer structure copolymer [C-1
[0] Synthesis) In a nitrogen atmosphere, 600 g of distilled water, 0.73 g of sodium lauryl sarcosinate as an emulsifier and 9.1 g of sodium stearate were added to a 2-liter polymerization vessel equipped with a stirring blade and a cooling tube, and the mixture was heated to 70 ° C. Heat and stir for 30 minutes. Then, 86.4 g of MMA, 3.6 g of EA and 0.18 g of ALMA as a polymerizable polyfunctional compound were added and stirred for 30 minutes, and 0.15 g of KPS was added to initiate polymerization. After 2 hours, it was confirmed by GC that all the respective monomers were consumed. Next, the obtained polymer latex 2
30 g (copolymer amount: 30 g) was transferred to a 0.5 liter autoclave, 0.267 g of Rongalit (formaldehyde sodium sulfoxylate), 0.013 g of disodium ethylenediaminetetraacetate and ferrous sulfate heptahydrate. 008 g was charged, and the temperature was raised to 50 ° C. while stirring and purging with nitrogen. After 1 hour, 0.1 g of cumene hydroperoxide was added, and 27.94 g of BA and 27.06 g of isoprene were fed over 2 hours. After completion of the feed, the reaction was continued for another 2 hours, and it was confirmed by GC that all the respective monomers were consumed. 285 g of the obtained copolymer latex (copolymer amount: 85 g) was transferred to a 2 liter polymerization vessel equipped with a stirring blade, a cooling tube and a dropping funnel under a nitrogen atmosphere, and heated to 70 ° C. Furthermore, K
After adding PS 0.1 g, MMA 14.4 g, EA 0.6
g and 0.23 g of n-OSH as a chain transfer agent were added dropwise from the dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes, and it was confirmed by GC that each monomer was consumed, and the polymerization was completed. The particle size of the obtained latex was 0.15 μm. This was cooled to −20 ° C. for 24 hours to aggregate and then the aggregate was taken out and
Washing was performed three times with hot water at 0 ° C. Further, it was dried under reduced pressure at 80 ° C. for 2 days to obtain a multilayer structure copolymer [C-10]. The results are shown in Table 2.

[0039]

[Table 2]

Synthesis Example 11 (methacrylic polymer [D-1
Synthesis of 1]) In a nitrogen atmosphere, 600 g of distilled water and 27.0 g of sodium lauryl sulfate as an emulsifier were added to a 2 liter polymerization vessel equipped with a stirring blade, a cooling tube and a dropping funnel, and heated to 70 ° C. to uniformly dissolve them. Let Then MMA110.6
4 g, EA 2.31 g and hexamethylene glycol methacrylic acid diester 34.76 g as a polymerizable polyfunctional compound were added and stirred for 30 minutes to obtain KPS 0.15.
g was added to initiate polymerization. After 1 hour, it was confirmed by GC that all the respective monomers were consumed. To the obtained polymer latex, 0.3 g of KPS was added, and 36.0 g of MMA, E
A 1.5 g and n-OSH 0.075 as chain transfer agent
The mixture of g was added dropwise from the dropping funnel over 2 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes, and it was confirmed that each monomer was consumed, and then the polymerization was completed. The particle size of the obtained latex was 0.05 μm. This was cooled to −20 ° C. and kept at this temperature for 24 hours for aggregation, and then the aggregate was taken out and washed with hot water at 80 ° C. three times. Further, it was dried under reduced pressure at 80 ° C. for 2 days to obtain a methacrylic polymer [D-11]. The results are shown in Table 3.

Synthesis Examples 12 to 14 (Synthesis of Methacrylic Polymers [D-12] to [D-14]) In Synthesis Example 11, the composition and amount of the emulsifier and the monomer mixture are shown in Table 3. The same operation as in Synthesis Example 11 was performed except that the methacrylic polymer [D-1
2] to [D-14] were obtained. The results are shown in Table 3.

[0042]

[Table 3]

Example 1 (Production of methacrylic resin composition and evaluation of physical properties) Methacrylic resin (Paragrass HR-10 manufactured by Kuraray Co., Ltd.)
00L) 42 parts by weight, multilayer structure copolymer [B-1] 38
Parts by weight and 20 parts by weight of the methacrylic polymer [D-11] were kneaded at 245 ° C. for 5 minutes using a batch-type kneader (Plastomill manufactured by Toyo Seiki Co., Ltd.). The obtained composition was finely pulverized and then compression thermoforming machine (F-3 manufactured by Shinto Metal Industry Co., Ltd.
7) was used to obtain 0.2 mm and 1 mm thick plates, and a small injection molding machine (CS-183MMX manufactured by CSI).
Was used to obtain a small test piece (32 × 3.2 × 6.4 mm). Various physical properties were evaluated using these, and the results are shown in Table 4.

Examples 2 to 9 and Comparative Examples 1 to 8 (Production of methacrylic resin composition and evaluation of physical properties) The types and blending amounts of the methacrylic resin, the multilayer structure copolymer and the methacrylic polymer are shown in Table 4 or Table 5. A methacrylic resin composition was produced in the same manner as in Example 1 except that the methacrylic resin composition was changed as shown, and various physical properties were evaluated.
The results of Examples 2 to 9 are shown in Table 4, and the results of Comparative Examples 1 to 8 are shown in Table 5.

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

INDUSTRIAL APPLICABILITY According to the present invention, a methacrylic resin composition which retains mechanical properties such as elastic modulus and various properties originally possessed by methacrylic resin such as transparency and is excellent in impact resistance and strain whitening resistance Things are offered.

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Claims (2)

(57) [Claims] 1. (A) 10-92% by weight of a methacrylic resin mainly composed of methyl methacrylate units, (B) a multilayer structure copolymer defined by the following [A] and / or (C) the following [B]: A methacrylic resin composition comprising 87 to 5% by weight of a multilayer structure copolymer defined by 1. and (D) 3 to 50% by weight of a methacrylic polymer defined by the following [C]. [A] (meth) acrylic acid alkyl ester having an alkyl group having 2 to 12 carbon atoms 69.9 to 94.9% by weight, styrene 30 to 5% by weight, and a polymerizable polyfunctional compound 0.1 to 5% by weight. % Of the monomer mixture or the following general formula (I): (In the formula, R represents a hydrogen atom or a methyl group.) 25 to 75% by weight of a diene monomer and an alkyl acrylate ester having 2 to 8 carbon atoms 75 to 2
A monomer mixture consisting of 5% by weight is polymerized, and 100 parts by weight of the obtained polymer is added with methyl methacrylate 80-99.9.
10-200, a monomer mixture consisting of 20% to 0.1% by weight and a monomer copolymerizable with methyl methacrylate.
A multilayer structure copolymer having an average particle size of 0.05 to 0.4 μm obtained by polymerizing parts by weight in the presence of a chain transfer agent. [II] 80 to 99.9% by weight of methyl methacrylate, 1 to 20% by weight of an alkyl acrylate whose alkyl group has 1 to 4 carbon atoms, and a polymerizable polyfunctional compound of 0.
A monomer mixture consisting of 1 to 3% by weight is polymerized, and 100 parts by weight of the resulting polymer has 2 to 12 carbon atoms in the alkyl group.
(Meth) acrylic acid alkyl ester of 69.9 to 9
A monomer mixture consisting of 4.9% by weight, 30 to 5% by weight of styrene and 0.1 to 5% by weight of a polymerizable polyfunctional compound, or a compound represented by the following general formula (I): (In the formula, R represents a hydrogen atom or a methyl group.) 25 to 75% by weight of a diene monomer and an alkyl acrylate ester having 2 to 8 carbon atoms 75 to 2
50 to 2000 parts by weight of a monomer mixture consisting of 5% by weight are polymerized, and 100 parts by weight of the resulting polymer are added with 80 to 99.9% by weight of methyl methacrylate and 20 to 20% of a monomer copolymerizable with methyl methacrylate. A multilayer structure copolymer having an average particle size of 0.05 to 0.5 μm obtained by polymerizing 10 to 100 parts by weight of a monomer mixture consisting of 0.1% by weight in the presence of a chain transfer agent. [C] methyl methacrylate 50 to 95 wt%, A acrylic acid alkyl esters having a carbon number of 1 to 4 alkyl groups 1
˜20% by weight and polymerizable polyfunctional compound 4-40
100% by weight of a polymer obtained by polymerizing a monomer mixture consisting of 1% by weight of methyl methacrylate and 80% to 99.5% by weight of methyl methacrylate and a monomer 2 copolymerizable with methyl methacrylate.
A methacrylic polymer having an average particle size of 0.01 to 0.4 μm obtained by polymerizing 10 to 300 parts by weight of a monomer mixture consisting of 0 to 0.5% by weight in the presence of a chain transfer agent. 2. The polymerizable polyfunctional compound constituting the multilayer structure copolymer defined by [a] or the multilayer structure copolymer defined by [b] is allyl alcohol and / or meta. The methacrylic resin composition according to claim 1, which is an ester of ril alcohol and at least one acid selected from the group consisting of acrylic acid, methacrylic acid, cinnamic acid, phthalic acid, terephthalic acid and isophthalic acid.