JP6205823B2 - Cross-linked methacrylic resin and scratch-resistant resin composition - Google Patents

Description

  The present invention relates to a crosslinked acrylic resin capable of improving scratch resistance without impairing the color developability and glossiness of the resin, and a scratch resistant resin composition containing the crosslinked methacrylic resin. The present invention also relates to a molded article formed by molding this scratch-resistant resin composition.

  In recent years, resin parts in the automobile field or the like are required to be usable without painting from the viewpoint of reducing manufacturing costs. Therefore, characteristics (required characteristics) required in addition to mechanical properties such as impact resistance have been widened. Among the characteristics required for resin parts, for example, in the case of automobile resin parts, scratch resistance is required such that the parts are not scratched during running or car washing, and the wax is not noticeable.

There are roughly two types of scratches on resin parts for automobiles: scratches (scratches) caused by hard and sharp objects such as stepping stones and dust during driving, and scratches (scratches) when wiped with work gloves or gauze. There is.
Depending on the resin, the two types of scratches have different susceptibility. For example, polymethylmethacrylate does not easily scratch, but easily scratches. On the other hand, polycarbonate has a problem that it is relatively hard to be scratched but is easily scratched.

  Scratches can be improved by adding a lubricating component such as silicone oil. On the other hand, regarding scratches, it has been proposed to add inorganic particles such as talc (Patent Document 1). However, when inorganic particles such as talc are added, there is a problem that glossiness is lowered.

  In addition, there is a report that in a polyester film, the shaving property of the film can be improved by adding a very small amount of crosslinked acrylic fine particles and inorganic fine particles (Patent Document 2). However, blending these has some effect on thin film, but in the case of a molded product having a predetermined thickness, it is not effective for scratch resistance because of the increased thickness. When the amount is increased, scratches are difficult to be attached, but the fine particles are aggregated to form a flaw and the surface appearance is deteriorated.

JP 2009-79117 A Japanese Patent Laid-Open No. 1-123836

  The present invention relates to a crosslinked methacrylic resin capable of improving the scratch resistance (scratch resistance, scratch resistance) without impairing the color developability and glossiness of the resin, and a scratch resistant resin containing the crosslinked methacrylic resin It is an object to provide a composition.

  As a result of repeated studies to solve the above problems, the present inventors have found that a crosslinked methacrylic resin having a specific degree of crosslinking and particle size swollen by chloroform can solve the above problems, and completed the present invention. I let you.

  That is, the gist of the present invention is as follows.

[1] A methacrylic monomer mixture containing 50 to 66% by mass of a crosslinkable monomer which is a polyfunctional monomer having two or more polymerizable double bonds and 34 to 50% by mass of methyl methacrylate. A polymer obtained by polymerization, having a volume average particle diameter of 0.01 to 0.5 μm, a gelation ratio of 90 to 100% when swollen with chloroform, and a swelling degree of 2 to 20 Cross-linked methacrylic resin (A) which is doubled.

[ 2 ] At least one monomer selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride in the crosslinked methacrylic resin (A) according to [1 ]. Graft-crosslinked methacrylic resin (B) obtained by graft polymerization (hereinafter referred to as “graft monomer”).

[ 3 ] Obtained by graft polymerization of the graft monomer in the presence of the cross-linked methacrylic resin (A), and the ratio of the cross-linked methacrylic resin (A) during graft polymerization is 40 to 80% by mass. The ratio of the monomer is 20 to 60% by mass (however, the total of the crosslinked methacrylic resin (A) and the graft monomer mixture is 100% by mass), and the graft ratio is 23 to 100%. The graft-crosslinked methacrylic resin (B) according to [ 2 ], which is characterized.

[ 4 ] Cross-linked methacrylic resin (A) of [1 ] and / or 5-20 parts by mass of graft-crosslinked methacrylic resin (B) of [2] or [3] , the cross-linked methacrylic resin (A) and graft-crosslinked A scratch-resistant resin composition comprising 80 to 95 parts by mass of a thermoplastic resin (C) other than the methacrylic resin (B) so as to be 100 parts by mass in total.

[ 5 ] When the other thermoplastic resin (C) is a rubbery polymer, at least one unit selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride. The scratch-resistant resin composition according to [ 4 ], comprising a graft polymer (D) obtained by graft polymerization of a monomer (hereinafter referred to as “graft monomer”).

[ 6 ] The gel content of the rubbery polymer is 55 to 99% by mass, the volume average particle diameter is 0.08 to 0.5 μm, and the graft polymer (D) is 40% of the rubbery polymer. Graft polymerization of ˜80 mass% and 20˜60 mass% of the graft monomer (however, the total of the rubbery polymer and the graft monomer is 100 mass%), and the graft ratio is The scratch-resistant resin composition according to [ 5 ], which is 23 to 100%.

[ 7 ] A molded product formed by molding the scratch-resistant resin composition according to any one of [ 4 ] to [ 6 ].

  According to the crosslinked methacrylic resin (A) and graft-crosslinked methacrylic resin (B) of the present invention, the scratch resistance (scratch resistance, scratch resistance) can be improved without impairing the color development and gloss of the resin. This can be used to provide a scratch-resistant resin composition excellent in various properties.

It is explanatory drawing of the evaluation method of scratch resistance (gauze wear) in an Example.

Hereinafter, the present invention will be described in detail.
In the present invention, “methacrylic ester” means “methacrylic acid ester (ester of methacrylic acid and alcohol)”, and “acrylic ester” means “acrylic acid ester (ester of acrylic acid and alcohol)”. Point.

[Crosslinked methacrylic resin (A)]
The cross-linked methacrylic resin (A) of the present invention is a polymer obtained by polymerizing a methacrylic monomer mixture containing a cross-linkable monomer and a methacrylic monomer. The gelation rate is 90 to 100%, the degree of swelling is 2 to 20 times, and the volume average particle diameter is 0.01 to 0.5 μm.

  The crosslinkable monomer is a polyfunctional monomer having two or more polymerizable double bonds, such as divinylbenzene, trivinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1 , 4-butylene glycol dimethacrylate, propylene glycol dimethacrylate, allyl methacrylate, triallyl isocyanurate, etc. These crosslinkable monomers may be used alone or in combination of two or more. Also good.

  The amount of the crosslinkable monomer used is preferably 36 to 66 mass% when the total of the crosslinkable monomer and methacrylic monomer used for the production of the crosslinked methacrylic resin (A) is 100 mass%. If the amount of the crosslinkable monomer used is less than 36% by mass, a sufficient effect of improving scratch resistance cannot be obtained. If the amount of the crosslinkable monomer used exceeds 66% by mass, it is blended in the resin. In this case, the cross-linked methacrylic resins (A) are aggregated to form a lump, which may deteriorate glossiness, color developability, and surface appearance.

  Examples of the methacrylic monomer include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, isobornyl methacrylate, Examples thereof include methacrylic esters such as benzyl methacrylate, phenyl methacrylate, glycidyl methacrylate, and hydroxyethyl methacrylate, and methacrylic acid. These monomers may be used individually by 1 type, and may use 2 or more types together.

  The amount of the methacrylic monomer used is preferably 34 to 64 mass% when the total of the crosslinkable monomer and the methacrylic monomer used for the production of the crosslinked methacrylic resin (A) is 100 mass%. When the amount of the methacrylic monomer used is less than 34% by mass, the cross-linked methacrylic resin (A) is aggregated to form a lump when blended in a resin, which may deteriorate glossiness, color developability, and surface appearance. In addition, when the amount of the methacrylic monomer used exceeds 64% by mass, a sufficient effect of improving scratch resistance cannot be obtained.

The methacrylic monomer mixture used for producing the crosslinked methacrylic resin (A) of the present invention may contain other copolymerizable monomers within a range not impairing the object of the present invention.
Other copolymerizable monomers include styrene, α-methyl styrene, o-, m- or p-methyl styrene, vinyl xylene, pt-butyl styrene, ethyl styrene and other aromatic vinyl, acrylonitrile, Vinyl cyanide such as methacrylonitrile, methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, isobornyl acrylate, benzyl Acrylic esters such as acrylate, phenyl acrylate, glycidyl acrylate, hydroxyethyl acrylate, acrylic acid, N-cyclohexylmaleimide, N-phenylmaleimide Such as maleimides and maleic anhydride. One of these other copolymerizable monomers may be used alone, or two or more thereof may be mixed and used.
When the methacrylic monomer mixture contains these other copolymerizable monomers, the content of the other copolymerizable monomer in the methacrylic monomer mixture is 20% by mass or less. Preferably there is.

  The crosslinked methacrylic resin (A) of the present invention is characterized in that the gelation rate by the chloroform swelling method shown below is 90 to 100% and the swelling degree is 2 to 20 times. If the gelation rate is less than 90%, the effect of improving scratch resistance cannot be obtained. If the degree of swelling is less than 2 times, the cross-linked methacrylic resin (A) tends to aggregate in the resin and the surface appearance deteriorates. If it is more than 20 times, the effect of improving scratch resistance cannot be obtained.

<Measurement and calculation method of gelation rate and swelling degree of crosslinked methacrylic resin (A)>
After about 0.1 g of the sample is immersed in chloroform for 2 hours to equilibrate and swell, the swollen sample is filtered, and the undissolved portion is taken out and vacuum dried. The gelation rate is defined as the weight fraction of the portion that did not dissolve after chloroform swelling with respect to the sample collected first, and is obtained by the following formula [I].
Gelation rate (%) = sample after vacuum drying (g) ÷ sample before swelling (g) × 100 (I)
The degree of swelling is defined as the rate of increase in the weight of the swollen sample with respect to the weight of the sample after vacuum drying, and is determined by the following formula [II].
Swelling degree (times) = swelled sample (g) / sample after vacuum drying (g) (II)

  Moreover, the volume average particle diameter of the crosslinked methacrylic resin (A) of the present invention is 0.01 to 0.5 μm, preferably 0.05 to 0.3 μm. When the volume average particle diameter of the cross-linked methacrylic resin (A) is less than 0.01 μm, the effect of improving scratch resistance cannot be obtained, and when it exceeds 0.5 μm, the surface appearance is deteriorated.

  The crosslinked methacrylic resin (A) can be produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method or an emulsion polymerization method, but the particle diameter is easy to control. Then, it is preferable to use an emulsion polymerization method.

  In order to make the gelation rate of the cross-linked methacrylic resin (A) within the preferable range, the cross-linkable monomer may be used in the range of 36 to 66% by mass. Moreover, what is necessary is just to use a crosslinkable monomer in said range also in order to make swelling degree of a crosslinked methacryl resin (A) into the said suitable range. Furthermore, the volume average particle diameter of the cross-linked methacrylic resin (A) can be controlled by the amount of the emulsifier used for the emulsion polymerization. When the total of the monomer and the methacrylic monomer is 100% by mass, the emulsifier may be used in an amount of 0.4 to 2.8% by mass.

[Graft-crosslinked methacrylic resin (B)]
The crosslinked methacrylic resin (A) of the present invention comprises at least one monomer selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride (hereinafter referred to as “ The graft-crosslinked methacrylic resin (B) obtained by graft polymerization may also be used. It is preferable that these monomers are graft-polymerized with the cross-linked methacrylic resin (A) because the dispersibility in the resin becomes better and the surface appearance becomes even better.

  As the graft monomer, methacrylic ester exemplified as the methacrylic monomer in the methacrylic monomer mixture, aromatic vinyl, vinyl cyanide, maleimides exemplified as other copolymerizable monomers, Examples thereof include maleic anhydride and acrylic ester, and one or more of them can be used. Among them, it is preferable to use styrene as the aromatic vinyl, at least one of α-methylstyrene, and acrylonitrile as the vinyl cyanide, and particularly 100% by mass of the graft monomer used for the graft polymerization to the crosslinked methacrylic resin (A). By using a monomer mixture having an aromatic vinyl content of 70 to 82% by mass and a vinyl cyanide content of 18 to 30% by mass, compatibility with the thermoplastic resin (C) described later can be achieved. The surface appearance is improved.

The graft crosslinked methacrylic resin (B) can be obtained by graft polymerization of the above graft monomer in the presence of the crosslinked methacrylic resin (A).
The ratio of the crosslinked methacrylic resin (A) at the time of graft polymerization is preferably 40 to 80% by mass, and the ratio of the graft monomer is preferably 20 to 60% by mass (however, the crosslinked methacrylic resin (A) and the graft are grafted). The total of the monomer mixture is 100% by mass). If the ratio of the cross-linked methacrylic resin (A) is in the above range, the cross-linked methacrylic resin (A) that improves scratch resistance is not deteriorated without deteriorating the color developability and glossiness. The dispersibility to the surface can be sufficiently increased, and the surface appearance is improved.

  The graft-crosslinked methacrylic resin (B) preferably has a graft ratio of 23 to 100% because the dispersibility in the resin becomes good.

In addition, the graft ratio (G) in this invention is calculated | required from following formula [III].
G = 100 (PE) / E [III]
P: Mass of acetone-insoluble matter (Graft-crosslinked methacrylic resin (B) or graft polymer (D) described later is washed with methanol, extracted with acetone, and separated into acetone-soluble and acetone-insoluble components with a centrifuge. The mass after the acetone-insoluble matter obtained was vacuum-dried (g))
E: Mass (g) of graft-crosslinked methacrylic resin (B) or graft polymer (D) before graft polymerization

  The graft-crosslinked methacrylic resin (B) can be produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, or an emulsion polymerization method.

  The volume average particle diameter of the graft-crosslinked methacrylic resin (B) obtained by graft polymerization of the graft monomer with the above-mentioned suitable graft ratio to the above-mentioned crosslinked methacrylic resin (A) having a volume average particle diameter is usually 0. .About 0.01 to 0.6 μm.

[Thermoplastic resin (C)]
The scratch-resistant resin composition of the present invention comprises the above-mentioned crosslinked methacrylic resin (A) and / or graft-crosslinked methacrylic resin (B) and heat other than the crosslinked methacrylic resin (A) and graft-crosslinked methacrylic resin (B). A plastic resin (C) is included.

  As the thermoplastic resin (C), a monomer having one or more of methacrylic ester of the methacrylic monomer and / or acrylic ester of the other copolymerizable monomer as a main component or Polymethacrylates and polyacrylates obtained by polymerizing the monomer mixture, polyolefins such as polyethylene and polypropylene, polycarbonate, polyphenylene ether, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyester, polysulfone, polyether ketone, poly Ethersulfone, fluororesin, silicone resin, polyester elastomer, polycaprolactone, aromatic polyester elastomer, polyamide elastomer, AS graft polyethylene, AS graft polymer Propylene, polystyrene, AS resin, styrene resin such as ABS resin and the like, which may be used alone or in combination of two or more thereof.

  The thermoplastic resin (C) in the present invention contains at least one monomer selected from the group consisting of a rubbery polymer, aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride. When the graft polymer (D) obtained by graft polymerization of is used, it is preferable because scratch resistance is also improved.

  Examples of the rubbery polymer forming the graft polymer (D) include polybutadiene, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, acrylic ester / butadiene copolymer, styrene / isoprene copolymer, Diene rubber such as natural rubber, acrylic rubber such as polybutyl acrylate, ethylene / propylene copolymer, ethylene / propylene / non-conjugated diene copolymer, olefin rubber such as ethylene / α-olefin copolymer, Examples thereof include silicone rubbers such as polyorganosiloxane, and these can be used alone or in admixture of two or more. Further, the structure of the rubbery polymer may take a composite form, for example, a polymer obtained by polymerizing an acrylic ester with polybutadiene or a polymer obtained by polymerizing an acrylic ester with polyorganosiloxane. Among these rubbery polymers, diene rubbers and olefin rubbers are preferred because the resulting resin composition has improved scratch resistance.

The presence or absence of crosslinking of the rubbery polymer is not particularly limited. However, the rubbery polymer is preferably crosslinked because of excellent color developability, and the gelation rate of the rubbery polymer is preferably 50 to 99% by mass.
The gelation rate of the rubber polymer indicates the degree of crosslinking of the rubber polymer. Specifically, the weighed rubber polymer is dissolved in an appropriate solvent for 20 hours, The insoluble matter remaining in the wire mesh is taken out, weighed, and weighed, and determined by the ratio (mass%) of the dried insoluble matter to the rubber polymer before being dissolved in the solvent. As a solvent used for dissolving the rubbery polymer, for example, toluene is used for diene rubber and olefin rubber, and acetone is used for acrylic rubber.

  The volume average particle diameter of the rubber polymer is preferably 0.08 to 0.5 μm. When the volume average particle diameter of the rubbery polymer is in the above range, the color developability of the resulting resin composition or molded product becomes good.

  The graft polymer (D) is at least one monomer selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride in the presence of a rubbery polymer. Can be obtained by graft polymerization. As the monomer used for graft polymerization (hereinafter referred to as “graft monomer”), the same monomers as those used for graft polymerization of the graft-crosslinked methacrylic resin (B) can be used. Among them, it is preferable to use styrene or α-methylstyrene as the aromatic vinyl and acrylonitrile as the vinyl cyanide, and particularly the content of the aromatic vinyl in 100% by mass of the graft monomer used for the graft polymerization. Is a monomer mixture having a content of 70 to 82% by mass and a vinyl cyanide content of 18 to 30% by mass, so that a crosslinked methacrylic resin (A), a graft-crosslinked methacrylic resin (B), or a thermoplastic resin (C) is obtained. This is preferable in terms of increasing the compatibility with and improving the surface appearance.

  The ratio of the rubbery polymer at the time of graft polymerization is preferably 40 to 80% by mass, and the ratio of the graft monomer is preferably 20 to 60% by mass (however, the ratio of the rubbery polymer and the graft monomer). The total is 100% by mass). When the ratio of the rubbery polymer is within the above range, the productivity of the graft polymer (D) is good, and the resin composition and its molded product are hardly scratched.

The graft polymer (D) preferably has a graft ratio of 23 to 100% because the color developability and molded appearance of the resin composition and molded product thereof are good.
The graft ratio of the graft polymer (D) can be measured by the same method as the method for determining the graft ratio of the graft-crosslinked methacrylic resin (B) described above.

  The graft polymer (D) is produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, an emulsion polymerization method, and the emulsion polymerization method is used in that it can be easily polymerized. preferable.

[Combination ratio]
The blended amount of the cross-linked methacrylic resin (A) and / or the graft cross-linked methacrylic resin (B) in the scratch-resistant resin composition of the present invention is less likely to reduce the glossiness and color developability of the resin composition and its molded product. When the total of the cross-linked methacrylic resin (A) and / or the graft cross-linked methacrylic resin (B) and the thermoplastic resin (C) is 100 parts by mass because scratch resistance is improved and the resin is easily dispersed in the resin. 5 to 20 parts by mass, preferably 8 to 15 parts by mass. For the same reason, the blending amount of the thermoplastic resin (C) in the resin composition of the present invention is such that the thermoplastic resin (C), the crosslinked methacrylic resin (A) and / or the graft-crosslinked methacrylic resin (B). When the total is 100 parts by mass, it is 80 to 95 parts by mass, preferably 85 to 92 parts by mass.

  Moreover, since the compounding amount of the graft polymer (D) in the resin composition of the present invention is less likely to be scratched on the resin composition and its molded product, the total thermoplastic resin (C) containing the graft polymer (D) is used. ) Is 100 parts by mass, it is preferably 0 to 95 parts by mass, particularly preferably 5 to 50 parts by mass.

[Additive]
In addition to the crosslinked methacrylic resin (A) and / or the graft-crosslinked methacrylic resin (B) and the thermoplastic resin (C), the scratch-resistant resin composition of the present invention includes a scratch-resistant resin composition and a molded product. As long as the physical properties are not impaired, other conventional additives such as lubricants, pigments, dyes, fillers (carbon black, titanium oxide, etc.), heat resistance agents, An oxidation deterioration inhibitor, a weathering agent, a release agent, a plasticizer, an antistatic agent, and the like can be blended.

[Method for Producing Scratch Resistant Resin Composition]
The scratch-resistant resin composition of the present invention can be produced by a known method using a known device. For example, there is a melt mixing method as a general method, and examples of an apparatus used in this method include an extruder, a Banbury mixer, a roller, and a kneader. Either a batch type or a continuous type may be employed for mixing. Moreover, there is no restriction | limiting in particular in the mixing order of each component, etc., All the components should just be mixed uniformly.

[Molding]
The molded article of the present invention is obtained by molding the scratch-resistant resin composition of the present invention. Examples of the molding method include an injection molding method, an injection compression molding machine method, an extrusion method, a blow molding method, a vacuum molding method, a pressure forming method, a calendar molding method, and an inflation molding method. Among these, the injection molding method and the injection compression molding method are preferable because they are excellent in mass productivity and a molded product with high dimensional accuracy can be obtained.
The molded product of the present invention is excellent in scratch resistance, color development, and molded appearance, and therefore can be suitably used particularly for automobile interior and exterior parts.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited to the following Example.

[Measurement method of physical properties]
(1) Gelation rate, degree of swelling and graft rate were determined by the methods described above.
In the following examples, P in the formula [III] is obtained by washing the graft-crosslinked methacrylic resin (B) or the graft polymer (D) with methanol, extracting with acetone, and then dissolving with acetone in a centrifuge. It is a mass (g) after separating into an acetone-insoluble content and vacuum-drying the obtained acetone-insoluble content.
(2) Volume average particle diameter The volume average particle diameter was measured using "Nanotrack 150" manufactured by Nikkiso Co., Ltd.

[Production Example 1: Cross-linked methacrylic resin (A1)]
In a pressure resistant reactor, 430 parts by weight of distilled water, 1.4 parts by weight of potassium alkenyl succinate, 50 parts by weight of methyl methacrylate, 50 parts by weight of 1,3-butylene glycol dimethacrylate, 2 parts by weight of allyl methacrylate, and t-butyl hydroper Oxide 0.26 parts by mass, ferrous sulfate heptahydrate 0.00015 parts by mass, sodium aldehyde sulfoxide 0.33 parts by mass, ethylenediamine-N, N, N ′, N′-tetracarboxylate disodium 0.00045 parts by mass The temperature was raised to 75 ° C. and the reaction was carried out for 2 hours. Then, it heated up to 90 degreeC and reaction was completed by hold | maintaining for 60 minutes. The contents were coagulated with an aqueous sulfuric acid solution, washed with a centrifugal dehydrator, repeatedly dehydrated, and dried to obtain a crosslinked methacrylic resin (A1).
The volume average particle diameter of the crosslinked methacrylic resin (A1) was 0.06 μm, the gelation rate was 99%, and the swelling degree was 10 times.

[Production Example 2: Cross-linked methacrylic resin (A2)]
A reaction was carried out under the same conditions as in Production Example 1 except that the amount of potassium alkenyl succinate was changed to 2.8 parts by mass to obtain a crosslinked methacrylic resin (A2).
The volume average particle diameter of the crosslinked methacrylic resin (A2) was 0.01 μm, the gelation rate was 99%, and the swelling degree was 10 times.

[Production Example 3: Cross-linked methacrylic resin (A3)]
A reaction was carried out under the same conditions as in Production Example 1 except that the amount of potassium alkenyl succinate was changed to 0.4 parts by mass to obtain a crosslinked methacrylic resin (A3).
The volume average particle diameter of the crosslinked methacrylic resin (A3) was 0.5 μm, the gelation rate was 99%, and the swelling degree was 10 times.

[Production Example 4: Cross-linked methacrylic resin (A4)]
Except that the amount of methyl methacrylate used was 62 parts by mass and the amount of 1,3-butylene glycol dimethacrylate used was 36 parts by mass, the reaction was carried out under the same conditions as in Production Example 1 to obtain a crosslinked methacrylic resin (A4). Obtained.
The volume average particle diameter of the crosslinked methacrylic resin (A4) was 0.06 μm, the gelation rate was 90%, and the swelling degree was 20 times.

[Production Example 5: Cross-linked methacrylic resin (A5)]
Except that the amount of methyl methacrylate used was 32 parts by mass and the amount of 1,3-butylene glycol dimethacrylate was 66 parts by mass, the reaction was carried out under the same conditions as in Production Example 1 to obtain a crosslinked methacrylic resin (A5). Obtained.
The cross-linked methacrylic resin (A5) had a volume average particle size of 0.06 μm, a gelation rate of 100%, and a degree of swelling of 2 times.

[Production Example 6: Cross-linked methacrylic resin (A6)]
The reaction was carried out under the same conditions as in Production Example 1 except that the amount of potassium alkenyl succinate was changed to 3.0 parts by mass to obtain a crosslinked methacrylic resin (A6).
The cross-linked methacrylic resin (A6) had a volume average particle size of 0.009 μm, a gelation rate of 99%, and a degree of swelling of 10 times.

[Production Example 7: Cross-linked methacrylic resin (A7)]
A reaction was carried out under the same conditions as in Production Example 1, except that the amount of potassium alkenyl succinate was 0.3 parts by mass, to obtain a crosslinked methacrylic resin (A7).
The volume average particle diameter of the crosslinked methacrylic resin (A7) was 0.6 μm, the gelation rate was 99%, and the swelling degree was 10 times.

[Production Example 8: Cross-linked methacrylic resin (A8)]
Except that the amount of methyl methacrylate used was 64 parts by mass and the amount of 1,3-butylene glycol dimethacrylate used was 34 parts by mass, the reaction was carried out under the same conditions as in Production Example 1 to obtain a crosslinked methacrylic resin (A8). Obtained.
The volume average particle size of the crosslinked methacrylic resin (A8) was 0.06 μm, the gelation rate was 89%, and the swelling degree was 21 times.

[Production Example 9: Cross-linked methacrylic resin (A9)]
The reaction was carried out under the same conditions as in Production Example 6 except that the amount of methyl methacrylate used was 30 parts by mass and the amount of 1,3-butylene glycol dimethacrylate was 68 parts by mass. Obtained.
The cross-linked methacrylic resin (A9) had a volume average particle size of 0.06 μm, a gelation rate of 100%, and a swelling degree of 1.5 times.

  Table 1 summarizes the physical properties of the crosslinked methacrylic resins (A1) to (A9).

[Production Example 10: Graft-crosslinked methacrylic resin (B1)]
After completing the reaction in Production Example 1, 0.4 parts by mass of potassium alkenyl succinate, 0.002 parts by mass of ferrous sulfate heptahydrate, 0.64 parts by mass of sodium aldehyde sulfoxide, ethylenediamine- 0.006 part by mass of disodium N, N, N ′, N′-tetracarboxylate was added. The internal temperature was raised to 65 ° C., and a mixture of 22 parts by mass of acrylonitrile, 78 parts by mass of styrene and 0.45 parts by mass of t-butyl hydroperoxide was added over 100 minutes, and the reaction was maintained by maintaining for 30 minutes. Completed. The reaction product latex was coagulated with an aqueous sulfuric acid solution, washed with water, and dried to obtain a graft-crosslinked methacrylic resin (B1).
The volume average particle diameter of the graft-crosslinked methacrylic resin (B1) was 0.07 μm, and the graft ratio was 27%.

[Production Example 11: Graft-crosslinked methacrylic resin (B2)]
A reaction was conducted in the same manner as in Production Example 10 except that the amount of acrylonitrile used was 18 parts by mass and the amount of styrene used was 82 parts by mass to obtain a graft-crosslinked methacrylic resin (B2).
The volume average particle diameter of the graft-crosslinked methacrylic resin (B2) was 0.07 μm, and the graft ratio was 23%.

[Production Example 12: Graft-crosslinked methacrylic resin (B3)]
The reaction was carried out in the same manner as in Production Example 10 except that the amount of acrylonitrile used was 30 parts by mass and the amount of styrene used was 70 parts by mass to obtain a graft-crosslinked methacrylic resin (B3).
The volume average particle diameter of the graft-crosslinked methacrylic resin (B3) was 0.07 μm, and the graft ratio was 27%.

[Production Example 13: Graft-crosslinked methacrylic resin (B4)]
The reaction was carried out in the same manner as in Production Example 10 except that the amount of acrylonitrile used was 17 parts by mass and the amount of styrene used was 83 parts by mass to obtain a graft-crosslinked methacrylic resin (B4).
The volume average particle diameter of the graft-crosslinked methacrylic resin (B4) was 0.07 μm, and the graft ratio was 22%.

[Production Example 14: Graft-crosslinked methacrylic resin (B5)]
The reaction was carried out in the same manner as in Production Example 10 except that the amount of acrylonitrile used was 31 parts by mass and the amount of styrene used was 69 parts by mass to obtain a graft-crosslinked methacrylic resin (B5).
The volume average particle diameter of the graft-crosslinked methacrylic resin (B5) was 0.07 μm, and the graft ratio was 22%.

[Production Example 15: Graft polymer (D1)]
Emulsified latex of ethylene / α-olefin copolymer having a gelation rate of 72% by mass and a volume average particle size of 0.25 μm (in terms of solid content), 0.15 parts by mass of sodium pyrophosphate, ferrous sulfate 0.006 part by mass of heptahydrate and 0.35 part by mass of fructose were charged, and the internal temperature was kept at 80 ° C. To this, a monomer mixture composed of 23.4 parts by mass of styrene and 6.6 parts by mass of acrylonitrile and 0.6 parts by mass of cumene hydroperoxide were simultaneously added dropwise over 140 minutes from different supply ports. Polymerization was performed. During this time, the internal temperature was controlled to be constant at 80 ° C. After completion of dropping, the mixture was kept at 80 ° C. for 100 minutes and then cooled to complete graft polymerization. The reaction product latex was coagulated with an aqueous sulfuric acid solution, washed with water, and dried to obtain a graft polymer (D1).
The graft ratio of the graft polymer (D1) was 31%.

[Production Example 16: Graft polymer (D2)]
A single amount composed of 170 parts by weight of distilled water, 70 parts by weight (in terms of solid content) of an emulsified latex of polybutadiene having a gelation rate of 95% by weight and a volume average particle size of 0.3 μm, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile Body mixture, disproportionated potassium rosinate 1 part by weight, sodium hydroxide 0.01 part by weight, sodium pyrophosphate 0.45 part by weight, ferrous sulfate heptahydrate 0.01 part by weight, dextrose 0.57 Participants were charged with parts by mass, 0.08 parts by mass of t-dodecyl mercaptan and 1.0 parts by mass of cumene hydroperoxide, the reaction was started from 60 ° C., and the temperature was raised to 75 ° C. during the course of 2 hours and a half after emulsion graft polymerization. Was completed. The latex of the reaction product was coagulated with an aqueous sulfuric acid solution, washed with water, and then dried to obtain a graft copolymer (D2).
The graft ratio of the graft polymer (D2) was 33%.

  As the thermoplastic resin (C), polymethyl methacrylate (“Acrypet VHSK” manufactured by Mitsubishi Rayon Co., Ltd.) and polycarbonate (“Iupilon S-3000F” manufactured by Mitsubishi Engineering Plastics) were used.

[Examples 1 to 19, Comparative Examples 1 to 10]
Each component is mixed with the composition (parts by mass) shown in Tables 2 to 4, and melt-kneaded at 240 ° C. using a 28 mm twin-screw extruder (“TEX-28V” manufactured by Nippon Steel) to form a pellet-shaped resin. A composition was obtained.
About the molded product which injection-molded the obtained resin composition, glossiness, coloring property, scratch resistance (pencil hardness, gauze abrasion), and surface appearance were evaluated by the following methods.
The evaluation results are shown in Tables 2-4.

<Glossiness>
The flat molded product having a thickness of 2 mm was measured with a digital gonioglossmeter (“UGV-5D” manufactured by Suga Test Instruments Co., Ltd.) under conditions of an incident angle of 60 ° and a reflection angle of 60 °.

<Color development>
0.5 parts by mass of carbon black was mixed and colored with respect to 100 parts by mass of the pellets of the resin composition, and a 100 × 100 mm (thickness 2 mm) black colored plate (test piece) was injection molded. About the obtained black colored board (test piece), L * was measured with the color difference meter. The lower L *, the more black and the better the color developability.

<Pencil hardness>
Based on JIS K5600, the pencil hardness of the molded product (test piece) was measured at a load of 750 g. The harder the pencil hardness, the harder it is to be scratched by a hard pointed object. F or higher was accepted.

<Gauze wear>
As shown in FIG. 1, a rod-shaped jig 2 having a tip portion 1 formed in a substantially hemispherical shape was prepared, and the tip portion 1 was covered with a laminated sheet S in which eight sheets of gauze were stacked. And the front-end | tip part 1 with which the lamination sheet S was covered is made to contact with the surface of the molded article (test piece) M so that the rod-shaped jig | tool 2 may become a right angle. The surface was slid in the horizontal direction (arrow X direction in the figure) and reciprocated 100 times. At that time, the applied load was 1 kg. After reciprocating 100 times, scratches on the surface of the molded product M were visually observed and evaluated according to the following four stages.
The better the gauze wear, the better the scuff resistance when the surface of the molded product is wiped with work gloves, gauze or cloth, or when clothing is rubbed. ○ The above was accepted.
◎: Scratches are scarce ○: Scratches are inconspicuous △: Scratches are prominent ×: Scratched scratches are noticeable when touched by hand

<Surface appearance>
About 100 * 100 mm (thickness 2mm) black colored board (test piece) which evaluated color development property, the presence or absence of a spot was observed visually and it evaluated in the following four steps. △ or more was accepted.
◎: No stuffiness ○: Little stuffiness is visible △: Slightly stuffiness is seen ×: The stuffiness is clearly visible

As shown in Examples 1 to 19 of Tables 2 and 3, according to each example using the crosslinked methacrylic resin (A) or the graft-crosslinked methacrylic resin (B) of the present invention, the color developability and glossiness are lowered. As a result, a scratch-resistant resin composition and a molded article having good scratch resistance were obtained. In particular, as shown in Example 6, by grafting a cross-linked methacrylic resin, the color developability and glossiness are not deteriorated, the scratch resistance is excellent, and the surface appearance is excellent. was gotten.
On the other hand, as shown in Table 4, the resin composition and molded product obtained in each comparative example were insufficient in at least one of glossiness, color development, scratch resistance, and surface appearance.
That is, Comparative Examples 1 and 2 were inferior in scratch resistance or surface appearance because the volume average particle diameter of the crosslinked methacrylic resin was outside the range of the present invention. Comparative Examples 3 and 4 were inferior in scratch resistance or surface appearance because the gelation rate or degree of swelling was outside the scope of the present invention. In Comparative Examples 5 to 10, the crosslinked methacrylic resin (A) of the present invention does not contain the graft crosslinked methacrylic resin (B) and exhibits the physical properties of the thermoplastic resin (C).

1 Tip 2 Jig S Laminated Sheet M Molded Product

Claims (7)

A methacrylic monomer mixture containing 50 to 66% by mass of a crosslinkable monomer which is a polyfunctional monomer having two or more polymerizable double bonds and 34 to 50% by mass of methyl methacrylate is polymerized. The obtained polymer has a volume average particle diameter of 0.01 to 0.5 μm, a gelation ratio of 90 to 100% when swollen with chloroform, and a swelling degree of 2 to 20 times. Cross-linked methacrylic resin (A).   In the crosslinked methacrylic resin (A) according to claim 1, at least one monomer selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride (hereinafter, Graft-crosslinked methacrylic resin (B) obtained by graft polymerization of “grafted monomer”.   It is obtained by graft polymerization of the graft monomer in the presence of the cross-linked methacrylic resin (A). The ratio of the cross-linked methacrylic resin (A) at the time of graft polymerization is 40 to 80% by mass. The ratio is 20 to 60% by mass (however, the total of the crosslinked methacrylic resin (A) and the graft monomer mixture is 100% by mass), and the graft ratio is 23 to 100%. Item 3. The graft-crosslinked methacrylic resin (B) according to Item 2.   The crosslinked methacrylic resin (A) according to claim 1 and / or 5 to 20 parts by mass of the graft-crosslinked methacrylic resin (B) according to claim 2 or 3, the crosslinked methacrylic resin (A) and the graft-crosslinked methacrylic resin (B). A scratch-resistant resin composition comprising 80 to 95 parts by mass of another thermoplastic resin (C) other than the above so as to be 100 parts by mass in total.   The other thermoplastic resin (C) has at least one monomer selected from the group consisting of aromatic vinyl, vinyl cyanide, acrylic ester, methacrylic ester, maleimide, and maleic anhydride in the rubbery polymer ( The scratch-resistant resin composition according to claim 4, further comprising a graft polymer (D) obtained by graft polymerization of a “graft monomer”.   The gel content of the rubbery polymer is 55 to 99% by mass, the volume average particle size is 0.08 to 0.5 μm, and the graft polymer (D) is 40 to 80% by mass of the rubbery polymer. % And 20 to 60% by mass of the graft monomer (however, the total of the rubber polymer and the graft monomer is 100% by mass), and the graft ratio is 23 to 100. The scratch-resistant resin composition according to claim 5, wherein the resin composition is scratch-resistant.   A molded article formed by molding the scratch-resistant resin composition according to any one of claims 4 to 6.

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