JP2005281562A - Styrene-based resin composition and transmission-type screen of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrene-based resin composition improved in impact strength and transparency in a well-balanced manner, and to provide an optical machine part given by using the resin composition, for example, a transmission-type screen. <P>SOLUTION: This styrene-based resin composition is obtained by together polymerizing a styrene-based monomer, methyl (meth)acrylate, and another (meth)acrylic acid ester which compose a copolymer (A) in the presence of a block copolymer rubber (B) which is composed of the styrene-based monomer and a diene-based monomer, wherein the resin composition contains particles (C) consisting mainly of the copolymer (A) and the block copolymer rubber (B), the styrene-based monomer is contained in the copolymer (A) in an amount of 30-60 wt%, and the particles (C) have a median diameter of 0.1-0.8 μm based on volume and a standard deviation of diameters of 0.1-0.3 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic resin composition excellent in impact strength and transparency, and a transmission type screen using the same.

Conventionally, it is known that a thermoplastic resin excellent in impact and transparency can be obtained by grafting styrene, methyl acrylate and alkyl acrylate to rubber particles having an average particle diameter of 0.1 to 0.5 μm (for example, (See Patent Document 1).
However, for optical applications such as lenses, there is a demand for thermoplastic resin materials that simultaneously satisfy a higher level of impact strength and transparency, but such materials are not provided.
Japanese Patent No. 3335384

  An object of the present invention is to provide a styrenic resin composition having improved impact strength and transparency in a well-balanced manner, and to provide optical application equipment obtained from such a resin composition, for example, a transmission screen.

As a result of intensive studies to solve the above problems, the present inventors have found that the obtained styrene-based resin composition meets this problem by controlling the average particle diameter and standard deviation of the rubber particle diameter. The present invention has been completed.
That is, the present invention relates to a block copolymer rubber of a styrene monomer and a diene monomer comprising a styrene monomer constituting the copolymer (A), methyl (meth) acrylate and other (meth) acrylate esters. A resin composition obtained by polymerization in the presence of (B), comprising the copolymer (A) and particles (C) mainly composed of a block copolymer rubber (B), and the copolymer The content of the styrenic monomer in (A) is 30 to 60% by weight, the volume-based median diameter of the particles is 0.1 to 0.8 μm, and its standard deviation is 0.1 to 0.00. It relates to a styrenic resin composition that is 3 μm.

  The styrenic resin composition of the present invention has excellent impact strength and transparency, and is useful for optical equipment such as a transmissive screen that brings about thinning and high brightness.

In the presence of the block copolymer rubber (B) of a styrene monomer and a diene monomer, the styrene resin composition of the present invention comprises a styrene monomer constituting the copolymer (A) and methyl (meth) acrylate. And other (meth) acrylic acid esters, and contains a copolymer (A) and particles (C) mainly composed of a block copolymer rubber (B).
The copolymer (A) is a main component of the resin composition of the present invention, and the content of the styrene monomer is 30 to 55% by weight, preferably 35 to 50% by weight, and the weight average molecular weight is preferable. Is from 100,000 to 200,000. Regarding the weight ratio of styrene monomer (A1), methyl (meth) acrylate (A2) and other (meth) acrylate ester (A3) in copolymer (A), transparency and impact strength are improved. From the point of view, A1 / (A2 + A3) = 30 / 75-60 / 40, preferably 35 / 65-50 / 50.

  Examples of the styrene monomer (A) constituting the copolymer (A) in the present invention include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylstyrene, and isobutylstyrene. , T-butylstyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc. Among them, styrene is preferred because of its excellent transparency. preferable.

  The methyl (meth) acrylate constituting the copolymer (A) is an essential component for imparting transparency to the resin composition of the present invention, and methyl methacrylate is particularly preferred because of its excellent transparency. .

  Further, as other alkyl acrylates constituting the copolymer (A), for example, ethyl acrylate, propyl acrylate, acrylic acid-n-butyl, acrylic acid-iso-butyl, acrylic acid-2-ethyl Hexyl and the like can be mentioned, and among these, acrylate-n-butyl is preferable because it is remarkably excellent in the impact strength improving effect of the sheet molded product.

  Examples of the styrene monomer constituting the block copolymer rubber (B) of the styrene monomer and diene monomer in the present invention include styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl. Styrene, ethyl styrene, isobutyl styrene, t-butyl styrene, o-bromo styrene, m-bromo styrene, p-bromo styrene, o-chloro styrene, m-chloro styrene, p-chloro styrene, etc. are mentioned. Is preferable from the viewpoint of excellent reactivity with the diene monomer.

  Examples of the diene monomer to be reacted with the styrenic monomer include butadiene, chloroprene, isoprene, 1,3-pentadiene, and the like. Among them, butadiene is preferable from the viewpoint of excellent reactivity with the styrene monomer.

Since the resin composition of the present invention is obtained by polymerizing the monomer constituting the copolymer (A) in the presence of the block copolymer rubber (B), the monomer is substantially grafted. It contains particles (C) mainly composed of a block copolymer rubber component. Such particles (C) optionally include a copolymer (A) and other polymers in the production of the resin composition.
The particles (C) have a volume-based median diameter in the resin composition of 0.1 to 0.8 μm, preferably 0.3 to 0.6 μm, and a standard deviation of 0.1 to 0.3 μm. Preferably it consists of 0.15-0.25 micrometer particle | grains. When the median diameter is less than 0.1 μm, the impact strength of the resulting composition is lowered, and when the median diameter exceeds 0.6 μm, the transparency is lowered. Further, when the standard deviation of the particle diameter is less than 0.1 μm, the impact strength of the resulting composition is lowered, and when the standard deviation exceeds 0.4 μm, the transparency is lowered.

The average particle size and standard deviation values of the particles (C) were measured with a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.).
The median diameter is an average particle diameter corresponding to 50% of the cumulative particle size.
The standard deviation represents the spread of the distribution and is obtained by the following equation.
Standard deviation = [Σ {(X (J) −Mean) ² × q (J) / 100}] ^1/2
J: Particle size division number q (J): Frequency distribution value (%)
X (J): representative diameter of the Jth particle size range (μm)
Mean: Average particle size

  The content of the particles (C) in the resin composition of the present invention is affected by the amount of the block copolymer rubber (B) used as the main component, but considering the characteristics of the resulting resin composition, the resin The amount of the block copolymer rubber (B) used is adjusted so that the content of the diene monomer in the composition is preferably 7 to 15% by weight, more preferably 9 to 13% by weight.

  In order to produce the resin composition of the present invention, in the presence of the block copolymer rubber (B), a styrene monomer, methyl (meth) acrylate, and other (meth) acrylic acid esters are used as essential components. Further, if necessary, graft copolymerization may be carried out together with other copolymerizable monomers by bulk-suspension polymerization, solution polymerization or bulk polymerization. Among these, bulk polymerization is preferable from the viewpoint of productivity and cost.

  In order to reduce the viscosity of the copolymer (A), an organic solvent may be added to the reaction system, and the organic solvent includes toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, anisole, Examples include cyanobenzene, dimethylformamide, N, N-dimethylacetamide, and methyl ethyl ketone.

The radical polymerization initiator to be used is not particularly limited, and for example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2- Peroxyketals such as bis (4,4-di-butylperoxycyclohexyl) propane,
Hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide, dialkyl peroxides such as di-t-butyl peroxide, dicumyl peroxide, di-t-hexyl peroxide, benzoyl peroxide, di Diacyl peroxides such as cinnamoyl peroxide, peroxyesters such as t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, t-butyl peroxyispropyl monocarbonate,
N, N′-azobisisobutylnitrile, N, N′-azobis (cyclohexane-1-carbonitrile), N, N′-azobis (2-methylbutyronitrile), N, N′-azobis (2,4 -Dimethylvaleronitrile), N, N′-azobis [2- (hydroxymethyl) propionitrile] and the like, and one or a combination of two or more of these may be used.

  Further, a chain transfer agent may be added to control the molecular weight of the copolymer. As the chain transfer agent, a monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer agents can be used. Examples of the monofunctional chain transfer agent include α-methylstyrene dimer, alkyl mercaptans, mercaptopropionic acid esters and the like.

  Polyfunctional chain transfer agents such as ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, etc. are esterified with thioglycolic acid or 3-mercaptopropionic acid. The thing which was done is mentioned.

  The styrene resin composition of the present invention can be produced by various methods such as a batch method and a continuous method in one or more reaction vessels in the presence of the block copolymer rubber (B). As shown in FIG. 1, it can be continuously obtained by a continuous bulk polymerization apparatus incorporating a tubular reactor having a static mixing element. That is, a mixed solution containing the monomers constituting the copolymer (A), the block copolymer rubber (B), a solvent, and the like is sent to a 20 liter stirred reactor (2) by a plunger pump (1), Initial polymerization was performed under dynamic mixing with a stirring blade. Subsequently, this mixed liquid is sent to the circulation polymerization line (I) by the gear pump (3). Circulation polymerization line (I) has a 2.5 inch inner diameter reactor in order from the inlet (SMX-type static mixer, 30 static mixing elements, built by Gebrüter Sulzer, Switzerland), (4), (5) and (6) And a gear pump (7) for circulating the mixed solution. Between the tubular reactor (6) and the gear pump (7), the tubular reactors (8), (9) and (10) and the gear pump (11) are the same as described above in order from the inlet to the non-circulation polymerization line (II). Are directly connected.

  If necessary, the resin composition of the present invention may contain any additive as long as transparency is not impaired. The type of additive is not particularly limited as long as it is generally used for blending plastics. For example, inorganic fillers such as silica, calcium carbonate, magnesium carbonate, calcium sulfate, and talc, organic fibers, titanium oxide , Pigments such as carbon black and iron oxide, dyes, stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide and other lubricants, mold release agents, organic polysiloxane, mineral oil, etc. Plasticizers, hindered phenolic and phosphorus antioxidants, flame retardants, UV absorbers, antistatic agents, glass fibers, carbon fibers, inorganic clays, reinforcing agents such as metal whiskers, foaming agents, other additives or these And the like.

When performing sheet molding using the molding material comprising the resin composition of the present invention, it is possible to obtain a colorless and transparent sheet under the same conditions as those for ordinary styrene resins.
Further, secondary molding of the above-described sheet, for example, container molding, can be easily performed under the same conditions as those for molding with a normal styrene resin.

  The resin composition of the present invention is used for applications other than those described above, such as injection molding, uniaxial extrusion molding, biaxial stretching extrusion molding, inflation extrusion molding, profile extrusion molding, vacuum molding, pressure forming, blow molding, bank molding, etc. Various molded products can be used as various molded products. Applications range widely, for example, optical equipment, i.e. parts of household electrical appliances such as audio players, various parts of office equipment such as copiers, printers, facsimiles, personal computers, IC carrier magazines, food containers, Examples include medical instrument parts, blister packages, and food packaging containers.

  In particular, the resin composition of the present invention is preferably used for a transmissive screen used in a rear projection type video apparatus. Typical examples of such a screen include a Fresnel lens and a lenticular lens. When the screen is made of the resin composition of the present invention, it can be made thinner and can exhibit high luminance.

(GPC measurement method)
High performance liquid chromatography (HLC-8220GPC manufactured by Tosoh Corporation), RI detector, TSKgel G6000H × 1 + G5000H × 1 + G4000H × l + G3000H × l + TSKguard columnH × lH, solvent THF, flow rate 1.0 ml / min, temperature 40 ° C.

(Charpy impact strength)
It measured according to JIS K7111: 96.

(Turbidity)
Measurement was performed according to JIS K7105 using a 2 mm thick test piece.
In the following examples, “parts” are units by weight unless otherwise specified.

Example 1
Styrene-butadiene copolymer rubber [5% styrene solution viscosity at 25 ° C. (hereinafter abbreviated as 5% SV): 10 centipoise, 1,2-vinyl bond ratio: 18%, styrene / butadiene weight ratio: 30/70] A mixed solution consisting of 16 parts, 42.5 parts of styrene, 53 parts of methyl methacrylate, 4.5 parts of butyl acrylate, and 21 parts of toluene was prepared, and further, 0.1 parts per 100 parts of the monomer mixture as a chain transfer agent. 18 parts n-octyl mercaptopropionate and 0.02 parts 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane as an organic peroxide and 100 parts monomer mixture Adipic acid with 0.01 part of cumene hydroperoxide added and 0.5 part of molecular end sealed with octyl alcohol for 100 parts of monomer mixture It was added polyester of butanediol was polymerized under the following conditions using the above apparatus.

Feed rate of mixed solution: 9 liters / hour Reaction temperature in stirring reactor (2): 115 ° C.
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 130-160 ° C
Reflux ratio: R = F1 / F2 = 6

The mixed solution obtained by polymerization was heated to 252 ° C., volatile components were removed under reduced pressure of 50 mmHg, and then pelletized to obtain particles extracted from the resin composition. The median diameter (average rubber particle diameter) of these particles is 0.47 μm, the standard deviation is 0.19 μm, and the Charpy impact strength of the resin composition obtained by polymerization is 13.4 KJ / m ² , haze 2.51%. Met.

Example 2
Styrene-butadiene copolymer rubber [5% styrene solution viscosity at 25 ° C. (hereinafter abbreviated as 5% SV): 10 centipoise, 1,2-vinyl bond ratio: 18%, styrene / butadiene weight ratio: 30/70] A mixed solution consisting of 16 parts, 43 parts of styrene, 52.5 parts of methyl methacrylate, 4.5 parts of butyl acrylate and 22.5 parts of toluene is prepared, and further, as a chain transfer agent, 100 parts of the monomer mixture. 0.1 part n-octyl mercaptopropionate and 0.02 part 2,2-bis (4,4-di-t-butylperoxycyclohexyl) per 100 parts monomer mixture as organic peroxide Adipine with propane and 0.01 parts cumene hydroperoxide added and 0.5 parts molecular end sealed with octyl alcohol for 100 parts monomer mixture The polyesters of butanediol was added and was polymerized under the following conditions using the above apparatus.

Feed rate of mixed solution: 9 liters / hour Reaction temperature in stirring reactor (2): 115 ° C.
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 130-160 ° C
Reflux ratio: R = F1 / F2 = 6

The mixed solution obtained by polymerization was heated to 252 ° C., volatile components were removed under reduced pressure of 50 mmHg, and then pelletized to obtain particles extracted from the resin composition. The median diameter of these particles was 0.48 μm, and the standard deviation was 0.21 μm. Moreover, the Charpy impact strength of the resin composition obtained by polymerization was 13.6 KJ / m ² and haze 2.4%. Various properties of the obtained composition were measured and are shown in Table 1.

Comparative Example 1
Styrene-butadiene copolymer rubber [5% styrene solution viscosity at 25 ° C. (hereinafter abbreviated as 5% SV): 10 centipoise, 1,2-vinyl bond ratio: 23%, styrene / butadiene weight ratio: 38/62] A mixed solution consisting of 18 parts, 48 parts of styrene, 42 parts of methyl methacrylate, 10 parts of butyl acrylate and 17 parts of toluene was prepared, and 0.1 part of n was added as a chain transfer agent to 100 parts of the monomer mixture. -Octyl mercaptopropionate and 0.02 part of t-butyl peroxybenzoate as an organic peroxide with respect to 100 parts of the monomer mixture were polymerized under the following conditions using the above apparatus.

Feed rate of mixed solution: 9 liters / hour Reaction temperature in stirred reactor (2): 115 ° C.
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 130-160 ° C
Reflux ratio: R = F1 / F2 = 6

The mixed solution obtained by polymerization was heated to 252 ° C., and after removing volatile components under a reduced pressure of 50 mmHg, a particle content extracted from the resin composition was obtained. The median diameter of the particles was 0.456 μm and the standard deviation was 2.49 μm. Moreover, the Charpy impact strength of the resin composition obtained by polymerization was 10.4 KJ / m ² and haze 7.6%. Various properties of the obtained composition were measured and are shown in Table 1.

Comparative Example 2
Styrene-butadiene copolymer rubber [5% styrene solution viscosity at 25 ° C. (hereinafter abbreviated as 5% SV): 10 centipoise, 1,2-vinyl bond ratio: 18%, styrene / butadiene weight ratio: 30/70] A mixed solution consisting of 16 parts, 42.5 parts of styrene, 53 parts of methyl methacrylate, 4.5 parts of butyl acrylate, and 17 parts of toluene was prepared. 1 part n-octyl mercaptopropionate and 0.02 part 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane as an organic peroxide with respect to 100 parts monomer mixture Adipic acid with 0.01 part cumene hydroperoxide added and 0.5 part molecular end sealed with octyl alcohol for 100 parts monomer mixture; Polyester was added with butanediol was polymerized under the following conditions using the above apparatus.

Feed rate of mixed solution: 9 liters / hour Reaction temperature in stirring reactor (2): 115 ° C.
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 130-160 ° C
Reflux ratio: R = F1 / F2 = 6

The mixed solution obtained by polymerization was heated to 252 ° C., volatile components were removed under reduced pressure of 50 mmHg, and then pelletized to obtain particles extracted from the resin composition. The median diameter of the particles was 0.55 μm and the deviation was 0.28. Moreover, the Charpy impact strength of the resin composition obtained by polymerization was 12.9 KJ / m ² and haze 4.4%. Various properties of the obtained composition were measured and are shown in Table 1.

Comparative Example 3
Styrene-butadiene copolymer rubber [5% styrene solution viscosity at 25 ° C. (hereinafter abbreviated as 5% SV): 10 centipoise, 1,2-vinyl bond ratio: 23%, styrene / butadiene weight ratio: 38/62] A mixed solution consisting of 12 parts, 48 parts of styrene, 47 parts of methyl methacrylate, 5 parts of butyl acrylate and 11 parts of toluene was prepared, and 0.15 parts of t was added as chain transfer agent to 100 parts of the monomer mixture. -0.02 part 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane and 0.01 part cumenehydro for 100 parts monomer mixture as dodecyl mercaptan and organic peroxide Adipic acid and butanediol with peroxide added and 1.8 parts molecular end capped with octyl alcohol for 100 parts monomer mixture Polyester, and the mixture was polymerized under the following conditions using the above apparatus.

Feed rate of mixed solution: 9 liters / hour Reaction temperature in stirring reactor (2): 115 ° C.
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 130-160 ° C
Reflux ratio: R = F1 / F2 = 6

The mixed solution obtained by polymerization was heated to 252 ° C., volatile components were removed under reduced pressure of 50 mmHg, and then pelletized to obtain particles extracted from the resin composition. The median diameter of these particles was 0.53 μm, and the standard deviation was 0.32 μm. Moreover, the Charpy impact strength of the resin composition obtained by polymerization was 8.2 KJ / m ² and haze 3.0%. Various properties of the obtained composition were measured and are shown in Table 1.

It is process drawing which shows an example of the continuous block polymerization line of the continuous block polymerization apparatus incorporating the tubular reactor which has a static mixing element.

Explanation of symbols

(1): The plunger pump
(2): Stirred reactor
(3): Gear pump
(4): Tubular reactor with static mixing elements
(5): Tubular reactor with static mixing elements
(6): Tubular reactor with static mixing elements
(7): Gear pump
(8): Tubular reactor with static mixing elements
(9): Tubular reactor with static mixing elements
(10): Tubular reactor with static mixing elements
(I): Circulation polymerization line
(II): Acyclic polymerization line

Claims (10)

Copolymer (A) styrene monomer, methyl (meth) acrylate, and other (meth) acrylate esters in the presence of block copolymer rubber (B) of styrene monomer and diene monomer In the resin composition obtained by polymerizing with styrene, the copolymer (A) and particles (C) mainly composed of the block copolymer rubber (B) are contained, and the styrene in the copolymer (A) Styrenic resin having a content of a system monomer of 25 to 55% by weight, a volume-based median diameter of the particles of 0.1 to 0.8 μm, and a standard deviation of 0.1 to 0.3 μm Composition. The styrene resin composition according to claim 1, wherein the copolymer (A) has a weight average molecular weight of 100,000 to 200,000. The styrene resin composition according to claim 1 or 2, wherein a styrene content in the copolymer (A) is 35 to 50% by weight. The styrene resin composition according to any one of claims 1 to 3, wherein the particles (C) have a median diameter of 0.3 to 0.6 µm. The styrenic resin composition according to any one of claims 1 to 4, wherein a standard deviation of a particle diameter of the particles (C) is 0.15 to 0.25 µm. The styrenic resin composition according to any one of claims 1 to 6, wherein the block copolymer rubber (B) has a weight average molecular weight of 100,000 to 200,000. The styrene resin composition according to any one of claims 1 to 6, wherein a content of the diene monomer in the resin composition is 9 to 13% by weight. A transmissive screen comprising the styrenic resin composition according to claim 1. 9. A transmission screen according to claim 8, comprising a Fresnel lens or a lenticular lens using the styrenic resin composition according to claim 1 as a constituent member. A rear projection type video apparatus comprising the transmission screen according to claim 8 or 9.

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