JP2023084451A - Resin composition, molding, and method for producing resin composition - Google Patents

Abstract

To provide a resin composition having excellent toughness and transparency and a method for producing the same, and a molding.SOLUTION: A resin composition comprises a methacrylic resin (A) and a styrene-maleic anhydride copolymer (B), the methacrylic resin (A) having a mass average molecular weight of 400,000 or more. Preferably, relative to 100 pts.mass of the methacrylic resin (A), the content of the styrene-maleic anhydride copolymer (B) is 0.1 pt.mass or more and 19.9 pts.mass or less. There are also provided: a molding of the resin composition; and a method for producing a resin composition by polymerizing a monomer mixture comprising methyl methacrylate in the presence of the styrene-maleic anhydride copolymer (B).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a resin composition, a molded article, and a method for producing a resin composition.

Transparent resins such as maleic anhydride-based copolymers are used in optical materials, medical materials, and the like, taking advantage of their excellent transparency. Recently, transparent resins containing maleic anhydride-based copolymers can easily bind amino groups and mercapto groups of peptides, which are bio-anchors, to maleic anhydride. It is applied to medical diagnostic microchannels that can modify the
On the other hand, maleic anhydride-based copolymers tend to yellow when heated, and have problems with workability due to their low toughness and elongation.

In order to solve these problems, studies have been made on mixing maleic anhydride copolymers with transparent resins such as (meth)acrylic resins, styrene copolymers, and styrene-maleic anhydride resins.
For example, in Patent Document 1, a transparent acrylic resin having a mass average molecular weight of 50,000 to 200,000, specifically about 100,000, is melted and mixed with a styrene-maleic anhydride resin.
Patent Document 2 describes a method for producing a resin composition in which a styrene-maleic anhydride resin and an acrylic resin are quantitatively supplied to an extruder and melt-kneaded using separate quantitative feeders. .

JP 2009-227944 A WO2016/186121

In the resin compositions proposed in Patent Documents 1 and 2, the molecular weight of the transparent resin is limited to a low one in order to ensure the fluidity of the transparent resin in a molten state, and the toughness when formed into a molded body is insufficient. Met. In addition, there is a problem of yellowing of the resin composition and the molded article due to heating during melting, and the transparency is insufficient.

An object of the present invention is to solve these problems. That is, an object of the present invention is to provide a resin composition excellent in toughness and transparency, a method for producing the same, and a molded article.

The present inventors have made extensive studies to solve the above problems, and as a result, the styrene-maleic anhydride copolymer (B) is allowed to coexist with a (meth)acrylic resin (A) having a predetermined molecular weight or more. The inventors have found that the problem can be solved, and have arrived at the present invention.
That is, the gist of the present invention is as follows.

[1] A resin composition containing a (meth)acrylic resin (A) and a styrene-maleic anhydride copolymer (B), wherein the (meth)acrylic resin (A) has a mass average molecular weight of 400,000 or more. thing.
[2] The styrene-maleic anhydride copolymer (B) according to [1] containing 0.1 parts by mass or more and 19.9 parts by mass or less relative to 100 parts by mass of the (meth)acrylic resin (A) Resin composition.
[3] A molded article obtained by molding the resin composition according to [1] or [2].
[4] A method for producing a resin composition, comprising polymerizing a monomer mixture containing methyl (meth)acrylate in the presence of a styrene-maleic anhydride copolymer (B).

The resin composition of the present invention is excellent in toughness and transparency. Therefore, it can be suitably used not only for microchannels for medical diagnosis, but also for existing transparent resin applications for illumination, for example, resins for optical members, building materials, vehicle materials, and the like.

Although the present invention will be described in detail below, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description unless it exceeds the gist of the present invention.
In addition, when the expression "~" is used in the present invention, it is used as an expression including numerical values or physical property values before and after it. Moreover, "(meth)acrylic acid" means at least one selected from "acrylic acid" and "methacrylic acid".
As used herein, "monomer" means an unpolymerized compound, and "repeating unit" means a unit derived from the monomer formed in the polymer by polymerization of the monomer. The repeating units may be units directly formed by a polymerization reaction, or some of the units may be converted to another structure by treating the polymer. Hereinafter, the "repeating unit" is simply referred to as "unit".
In the present specification, "% by mass" and "parts by mass" and "% by weight" and "parts by weight" are synonymous, and "% by mass" means the content of a predetermined component contained in the total amount 100% by mass Show a percentage.

[Resin composition]
The resin composition of the present invention contains a (meth)acrylic resin (A) and a styrene-maleic anhydride copolymer (B).

<(Meth) acrylic resin (A)>
The (meth)acrylic resin (A) is one of the constituent components of the resin composition of the present invention.

Monomers constituting the (meth)acrylic resin (A) that can be used in the resin composition of the present invention are preferably (meth)acrylic acid alkyl ester monomers having one or more polymerizable vinyl groups in the molecule. , methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, (meth)acrylic acid 2-ethylhexyl, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, n-(meth)acrylate amyl, isoamyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, (meth)acrylic acid Examples include (meth)acrylic acid ester compounds such as ethoxyethyl, 2-naphthyl (meth)acrylate, and phenoxymethyl (meth)acrylate. Among these, alkyl (meth)acrylate compounds having 1 to 8 carbon atoms in the alkyl group portion are preferable, and methyl (meth)acrylate is more preferable.

The (meth)acrylic resin (A) contained in the resin composition of the present invention has a mass average molecular weight of 400,000 (400,000) or more, preferably 420,000 or more, and more preferably 450,000 or more. If the (meth)acrylic resin (A) has a mass average molecular weight of less than 400,000, the toughness is low, that is, the bending stress and breaking strain described below are low, and sufficient mechanical strength cannot be obtained.

On the other hand, the upper limit of the mass average molecular weight of the (meth)acrylic resin (A) is not particularly limited, but is preferably 1,000,000 or less, more preferably 900,000 or less, and even more preferably 800,000 or less. If the (meth)acrylic resin (A) has a mass-average molecular weight of more than 1,000,000, the flowability during heating is lowered, and moldability is deteriorated.

The mass average molecular weight of the (meth)acrylic resin (A) is a value measured by gel permeation chromatography (GPC) using standard polymethyl methacrylate as a standard sample.

The resin composition of the present invention may contain only one of the above (meth)acrylic resins (A), or may contain two or more different monomer compositions, mass-average molecular weights, etc. good.

<Styrene-maleic anhydride copolymer (B)>
The styrene-maleic anhydride copolymer (B) is one of the constituent components of the resin composition of the present invention.

The content of maleic anhydride units in 100 parts by mass of the styrene-maleic anhydride copolymer (B) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 19.9 parts by mass or less, and particularly , 15 parts by mass or less. If the content of maleic anhydride units is equal to or less than the above upper limit, the toughness of the resulting molded article will be excellent.

On the other hand, the content of maleic anhydride units in 100 parts by mass of the styrene-maleic anhydride copolymer (B) is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and most preferably 10 parts by mass or more. If the content of maleic anhydride units is at least the above lower limit, yellowing is unlikely to occur, and bending stress and bending strain, which will be described later, are high, and toughness is excellent.

The styrene-maleic anhydride copolymer (B) preferably has a mass average molecular weight of 1,000 to 100,000, more preferably 5,000 to 50,000. When the weight average molecular weight of the styrene-maleic anhydride copolymer (B) is at least the above lower limit, the strength is excellent, and when it is at most the above upper limit, the moldability is excellent.

Incidentally, the mass average molecular weight of the styrene-maleic anhydride copolymer (B) is a conversion value measured using standard polystyrene as a standard sample and using gel permeation chromatography (GPC), but even if it is a commercial product, catalog values can be adopted.

A commercially available product can be used as the styrene-maleic anhydride copolymer (B) according to the present invention. Specific examples include Sartomer SMA base resin (styrene-maleic anhydride copolymer) SMA1000 (5,500), SMA2000 (7,500), SMA3000 (9,500), F30 (9,500), Polyscope SMA resins XIRAN® 9000 (10,000), 6000 (10,000), 4000 (10,000), 1000 (5,000) and the like can be used. In the above product names, the numbers in parentheses represent the weight average molecular weights.

The resin composition of the present invention may contain only one type of the styrene-maleic anhydride copolymer (B) described above, or may contain two or more types having different monomer compositions, mass-average molecular weights, and the like. There may be.

<Content ratio>
The resin composition of the present invention preferably contains 30 parts by mass or less of the styrene-maleic anhydride copolymer (B) with respect to 100 parts by mass of the (meth)acrylic resin (A), and may contain 25 parts by mass or less. More preferably, it contains 19.9 parts by mass or less, and particularly preferably 15 parts by mass or less. If the content of the styrene-maleic anhydride copolymer (B) is equal to or less than the above upper limit, the bending stress and bending strain described later will be high and the toughness will be excellent.

On the other hand, the lower limit of the content of the styrene-maleic anhydride copolymer (B) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more. When the content of the styrene-maleic anhydride copolymer (B) is at least the above lower limit, the bending stress and bending strain, which will be described later, are high and the toughness is excellent.

<Other ingredients>
The resin composition of the present invention may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, lubricants, dyes, flame retardants, etc., as long as they do not impair the effects of the present invention. .
When the resin composition of the present invention contains these other components, the viewpoint of effectively obtaining the effects of the present invention by including the (meth)acrylic resin (A) and the styrene-maleic anhydride copolymer (B). Therefore, the total content of the (meth)acrylic resin (A) and the styrene-maleic anhydride copolymer (B) in the resin composition of the present invention is 95 to 100% by mass, particularly 98 to 100% by mass. is preferred.

[Method for producing resin composition]
The method for producing the resin composition of the present invention is not particularly limited, but according to the method for producing the resin composition of the present invention, in the presence of the styrene-maleic anhydride copolymer (B), A method of polymerizing a monomer mixture containing an acrylic acid alkyl ester monomer, preferably methyl (meth)acrylate, tends to stabilize the molecular weight of the (meth)acrylic resin (A), resulting in a resin composition excellent in toughness and transparency. can be obtained, which is preferable.

Specifically, in this method, a styrene-maleic anhydride copolymer (B) is dissolved in a (meth)acrylic acid alkyl ester monomer, which is a raw material of a (meth)acrylic resin (A), and injected into a mold. After that, bulk polymerization (casting polymerization) is carried out, and then the obtained polymer is taken out from the mold, whereby the resin composition of the present invention can be obtained.

The above casting polymerization method is particularly preferable for applications requiring sufficient toughness or transparency.

Examples of the polymerization reaction format of the casting polymerization method include radical polymerization and anionic polymerization. Among these, free radical polymerization is preferred in terms of polymerization control.

Examples of radical polymerization initiators used for radical polymerization include 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, Azo compounds such as 2,2′-azobis-(2,4-dimethylvaleronitrile); and lauroyl peroxide, diisopropyl peroxydicarbonate, benzoyl peroxide, bis(4-t-butylcyclohexyl) peroxydicarbonate , t-butyl peroxyneodecanoate, t-hexylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexa Examples include organic peroxide compounds such as noate and t-hexylperoxyisopropyl monocarbonate. These can be used individually by 1 type or in combination of 2 or more types.

The amount of the radical polymerization initiator to be added is from 0.02 to 0.02 parts per 100 parts by mass of the (meth)alkyl (meth)acrylate monomer, from the viewpoint of the polymerizability of the (meth)acrylic acid alkylester monomer and the surface appearance of the resulting molded product. 1 part by weight is preferred.

Examples of the mold used for casting polymerization include a mold made of a pair of plate-shaped bodies such as inorganic glass, chromium-plated metal plate, stainless steel plate, etc., facing each other with soft gaskets arranged at the ends of the same A mold composed of gaskets installed at both ends of a pair of endless belts running at the same speed in the same direction can be used.

The polymerization temperature for obtaining the resin composition of the present invention is preferably 40° C. or higher, more preferably 50° C. or higher, from the viewpoint of increasing the polymerizability of the (meth)acrylic acid alkyl ester monomer. Moreover, the polymerization temperature for obtaining the resin composition of the present invention is preferably 180° C. or lower, more preferably 150° C. or lower, from the viewpoint of suppressing coloring and appearance defects of the resin composition.

The polymerization time for obtaining the resin composition of the present invention is appropriately determined according to the progress of polymerization.

In addition, the (meth)acrylic acid alkyl ester monomer is partially polymerized in advance in the presence of a radical polymerization initiator before the styrene-maleic anhydride copolymer (B) is added, and the (meth)acrylic acid alkyl ester is obtained. A syrup containing 5 to 30% by mass of a monomer polymer and 95 to 70% by mass of a (meth)acrylic acid alkyl ester monomer is prepared, and the styrene-maleic anhydride copolymer (B) is dissolved in the syrup. Further polymerization may be carried out in the presence of radical polymerization initiators. By doing so, the surface of the resin sheet can be made smooth, which is preferable.

[Molded body]
The molded article of the present invention is obtained by molding the resin composition of the present invention, and its shape is not particularly limited. It is particularly useful as a sheet-shaped molding (resin sheet).

The thickness of the resin sheet made of the resin composition of the present invention is appropriately designed according to its use, but is usually 0.3 to 10 mm. The thickness of the resin sheet is preferably 0.4 to 5 mm from the standpoint of handleability and practical use of the resin sheet.

Methods for producing a resin sheet made of the resin composition of the present invention include, for example, a method for directly obtaining a resin sheet by cast-polymerizing raw materials for obtaining the resin composition, and a method for preparing pellets or powder of the resin composition. and then subjecting it to extrusion molding or injection molding to obtain a resin sheet. Among these, the method of directly producing a resin sheet by the above-described cast polymerization is preferred in terms of the transparency, toughness and productivity of the resulting resin sheet.

The molded article of the present invention, particularly the resin sheet, is suitable for, for example, liquid crystal monitors, personal computers, tablets, smartphones, mobile phones, back plates of electronic blackboards, signage and bathtubs, and structural materials such as microchannels for medical diagnosis. used for

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples.

<raw materials>
The abbreviations of the compounds used in Examples and Comparative Examples are as follows.
MMA: methyl methacrylate (trade name: Acryester (registered trademark) M manufactured by Mitsubishi Chemical Corporation)
Styrene-maleic anhydride copolymer (B-1): maleic anhydride unit content: 11 mass %, styrene unit: maleic anhydride unit molar ratio = 8: 1 (trade name: XIRAN (registered trademark) 9000 (molecular weight : 10,000) manufactured by Polyscope)
Styrene-maleic anhydride copolymer (B-2): maleic anhydride unit content: 19 mass%, styrene unit: maleic anhydride unit molar ratio = 6: 1 (trade name: XIRAN (registered trademark) 6000 (molecular weight : 10,000) manufactured by Polyscope)
Styrene-maleic anhydride copolymer (B-3): maleic anhydride unit content: 14 mass %, styrene unit: maleic anhydride unit molar ratio = 4: 1 (trade name: XIRAN (registered trademark) 4000 (molecular weight : 10,000) manufactured by Polyscope)

<Evaluation method>
Evaluations in Examples and Comparative Examples were carried out by the following methods.

(bending stress/bending strain)
As an index of the mechanical strength (toughness) of the resin sheet in the present invention, bending stress and bending strain were measured by the following methods.
The resin sheets (thickness 3 mm) obtained in Examples and Comparative Examples were cut into rectangular parallelepiped test pieces of 80 mm × 10 mm × 3 mm using a panel saw (trade name: SZIVG-4000, manufactured by Thinks Corporation). made. The obtained test piece was allowed to stand for 18 hours under conditions of a temperature of 25° C. and a relative humidity of 50% RH, and then a three-point bending tester (device name: Strograph TF, manufactured by Toyo Seiki Co., Ltd.) was used. , In accordance with JIS K7171, a bending test was performed on each test piece at a bending speed of 1.8 mm / min, and the stress at the time of breakage of the test piece was measured as bending stress (MPa), and the strain at break was measured as bending strain (%). bottom. Bending stress and bending strain were measured once for each test piece using three test pieces, and their average values were taken.
Bending stress was evaluated according to the following criteria.
AA: Bending stress (MPa) is 140 (MPa) or more.
A: Bending stress of 120 to 139 (MPa).
B: Bending stress was less than 120 (MPa).
Bending strain was evaluated according to the following criteria.
AA: Bending strain (%) is 7.0 (%) or more.
A: Bending stress of 5.0 to 6.9 (%).
B: Bending stress was less than 5.0 (%).

(Total light transmittance)
As an index of the transparency of the resin sheet in the present invention, the total light transmittance was measured by the following method.
Based on JIS-K7361-1, the resin sheets (thickness 3 mm) obtained in Examples and Comparative Examples were measured three times using a spectral haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.). , an average value was obtained and evaluated according to the following criteria.
AA: Total light transmittance is 93 (%) or more A: Total light transmittance is 92 (%) or less

(Haze value)
As an index of the transparency of the resin sheet in the present invention, the haze value was measured by the following method.
Based on JIS-K7136, the resin sheets (thickness 3 mm) obtained in Examples and Comparative Examples were measured three times using a spectral haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.), and the average A value was obtained and evaluated according to the following criteria.
AA: Haze value is 0.2 or less A: Haze value is 0.3 to 1.0
B: The haze value exceeded 1.

(yellow index)
As an indicator of the transparency of the resin composition in the present invention, a yellow index (YI) was measured by the following method.
Based on ISO 17223, the resin sheets (thickness 3 mm) obtained in Examples and Comparative Examples were measured three times using a spectroscopic color difference meter (model name "SE-7700", manufactured by Nippon Denshoku Industries Co., Ltd.). Measurements were taken, average values were obtained, and evaluation was made according to the following criteria.
AA: YI is 0.3 or less.
A: YI is 0.3 to 1.0.
B: YI exceeded 1.0.

(Weight average molecular weight (Mw)
The mass average molecular weight (Mw) of the (meth)acrylic resin was measured by gel permeation chromatography (GPC).
A solution obtained by dissolving the resin sheet (thickness 3 mm) obtained in Examples and Comparative Examples in tetrahydrofuran was used as a sample for GPC measurement. In the GPC measurement, two separation columns (manufactured by TSK-Gel, trade name: SUPER HM-H) are used in series in a high-performance liquid chromatography measurement device (manufactured by Tosoh Corporation, trade name: HLC-8320 type). bottom. A differential refractometer was used as a detector. Separation column temperature: 40°C, moving bed: tetrahydrofuran (THF), flow rate of moving bed: 0.6 ml/min, sample injection amount: 10 µL. Using several types of polymethyl methacrylate (Mw 340 to 1,950,000) with known molecular weights as standard polymers, standard polymer equivalent molecular weights were determined.

[Example 1]
100 parts by mass of MMA (methyl methacrylate) was put into a reactor (polymerization vessel) equipped with a cooling pipe, a thermometer and a stirrer, and stirred. After bubbling with nitrogen gas, heating was started. When the internal temperature reached 80° C., 0.05 part by mass of 2,2′-azobis-(2,4-dimethylvaleronitrile) as a radical polymerization initiator was added. After further heating to an internal temperature of 100° C., it was held for 10 minutes. The reactor was then cooled to room temperature to obtain a syrup, a viscous mixture in which MMA was partially polymerized. The syrup had a polymerization rate of about 20% by mass and contained 20% by mass of polymer and 80% by mass of monomer.
After that, 1 part by mass of styrene-maleic anhydride copolymer (B-1), 0.2 parts by mass of t-hexylperoxypivalate, and 0.01 part by mass of sodium dioctylsulfosuccinate were added to 100 parts by mass of syrup. , completely dissolved at room temperature to form a polymerizable starting material.
After removing dissolved air in the polymerizable raw material under reduced pressure, the polymerizable raw material was injected into a pair of mirror-finished glass polymerization cells having a thickness of 10 mm and a thickness tolerance of ±0.001 mm (interval: 3 mm).
The polymerization cell into which the polymerizable raw material was injected was held in a hot water bath at 80°C for 60 minutes, then taken out and heated in an oven at 130°C for 30 minutes to completely harden the syrup. After the polymerization cell was cooled to room temperature, the polymerization cell was peeled off to obtain a resin sheet. Table 1 shows the evaluation results of the obtained resin sheet.

[Examples 2 to 7]
A resin sheet was obtained under the same conditions as in Example 1, except that the type and amount of the styrene-maleic anhydride copolymer (B) were as shown in Table 1. Table 1 shows the evaluation results of the obtained resin sheet.

[Comparative Example 1]
A resin sheet was obtained under the same conditions as in Example 1, except that the styrene-maleic anhydride copolymer (B) was not added. Table 1 shows the evaluation results of the obtained resin sheet.

<Evaluation results>
The resin sheets of Examples 1 to 7 were colorless and transparent, had a bending stress of 140 (MPa) and a bending strain of 7.0 (%), and had excellent toughness.

The resin sheet of Comparative Example 1 was colorless and transparent, but had a bending strength of 120 (MPa) and a bending strain of 5.0 (%), which are lower than those of Examples 1-7. This difference is considered to be due to the absence of the styrene-maleic anhydride copolymer (B).

Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples. Additions, omissions, substitutions, and other changes in configuration are possible without departing from the scope of the present invention.
Moreover, the present invention is not limited by the foregoing description, but only by the appended claims.

The resin composition of the present invention and a molded article such as a resin sheet made of this resin composition are excellent in toughness and moldability. In addition, since there is almost no yellowing and high transparency, it is suitable not only for microchannels for medical diagnosis, but also for existing transparent resin applications for lighting, such as resins for optical members, building materials, vehicle materials, etc. Available.

Claims (4)

(Meth) acrylic resin (A) and styrene-maleic anhydride copolymer (B),
A resin composition, wherein the (meth)acrylic resin (A) has a mass average molecular weight of 400,000 or more. The resin composition according to claim 1, which contains 0.1 parts by mass or more and 19.9 parts by mass or less of the styrene-maleic anhydride copolymer (B) with respect to 100 parts by mass of the (meth)acrylic resin (A). . A molded article obtained by molding the resin composition according to claim 1 . A method for producing a resin composition, comprising polymerizing a monomer mixture containing methyl (meth)acrylate in the presence of a styrene-maleic anhydride copolymer (B).