JP2002309056A - Impact-resistant modifier for acrylic resin, method for producing the same, acrylic resin composition and method for modifying impact resistance of acrylic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact-resistant modifier consisting essentially of a diene-based graft copolymer, capable of impacting sufficient impact resistance, having good powder characteristics and capable of keeping the transparency even when further compounded in an acrylic resin. SOLUTION: This impact-resistant modifier is composed of polymer particles in which both of diene-based graft copolymer (A) latex and rigid non-elastic polymer (B) latex are coagulated and a glass transition temperature of the rigid non-elastic polymer is higher than a temperature exhibited when coagulated and refractive index nDC of the acrylic resin, refractive index nDA of the diene-based graft copolymer and refractive index nDB of the rigid non-elastic polymer satisfy the relationships represented by the formulas -0.005<=nDC-nDA<=+0.005 and -0.005<=nCD-nDB<=+0.005.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an impact modifier for acrylic resin, a method for producing the same, an acrylic resin composition, and a method for modifying the impact resistance of acrylic resin.

[0002]

2. Description of the Related Art Acrylic resin is widely used for lighting equipment, signboards, various building materials, sound insulation boards, etc. due to its excellent transparency, surface gloss, weather resistance, mechanical properties, etc. There is a disadvantage that it is not enough. The most common method for modifying the impact resistance of an acrylic resin is to blend elastic polymer particles obtained by emulsion polymerization with the acrylic resin. Examples of the elastic polymer used herein include a diene-based graft copolymer containing butadiene as a main component and an acrylic rubber-like polymer having a glass transition temperature lower than room temperature, mainly containing acrylates. No.

[0003] In order to blend an elastic polymer produced by emulsion polymerization with an acrylic resin, it is first necessary to recover the elastic polymer as particles from the emulsion polymerization latex.
As a method for recovering particles from latex, there is a method in which latex is brought into contact with a coagulant such as an acid or a salt to coagulate, and then dehydrated and dried to recover particles. Among the elastic polymer particles recovered by such a method, diene-based graft copolymers are particularly excellent in that they have higher impact resistance-imparting ability than acrylic rubber-like polymers. However, since the diene-based graft copolymer has a low glass transition temperature, there is a problem that the obtained particles are likely to be blocked during storage. In addition, powder fluidity is poor, and problems such as clogging of a transport line are likely to occur. When the content of the rubber component in the diene-based graft copolymer is increased in order to further improve the impact resistance-imparting ability, these tendencies are further increased, causing inconvenience. Therefore, anti-blocking properties, powder flowability,
There is a strong demand for the development of elastic polymer particles having excellent powder properties such as bulk density.

On the other hand, if an acrylic resin is blended with a diene-based graft copolymer in order to improve the impact resistance, there is also a problem that the transparency of the acrylic resin is reduced and its use range is narrowed. In other words, the diene-based graft copolymer used as an impact modifier for a transparent acrylic resin not only has excellent powder properties as polymer particles, but also when blended with an acrylic resin,
It is necessary that impact resistance can be imparted without impairing the transparency of the acrylic resin. As a method for producing polymer particles having excellent powder properties, JP-A-54-7458 discloses
A method has been proposed in which a salt and a hard inelastic polymer are added to a coagulation tank in which an acrylic rubbery polymer is present to coagulate.

[0005]

However, although the above-mentioned publication describes an acrylic rubbery polymer, it does not disclose the case of obtaining diene-based graft copolymer particles having excellent powder properties. . Further, the effect of improving the powder performance is not sufficiently exhibited. Thus, a diene-based graft copolymer which has excellent powder properties and does not impair the transparency even when blended with a transparent acrylic resin has not yet been reported.

The present invention has been made in view of the above circumstances, and provides a diene-based graft which can impart sufficient impact resistance, has good powder properties, and can maintain its transparency even when blended with an acrylic resin. It is an object of the present invention to provide an impact resistance modifier containing a copolymer as a main component and to improve the impact resistance of an acrylic resin.

[0007]

The impact modifier for an acrylic resin of the present invention is an impact modifier incorporated in an acrylic resin, and comprises a diene-based graft copolymer (A) latex. The hard inelastic polymer (B) is composed of coagulated polymer particles together with a latex, and the glass transition temperature of the hard inelastic polymer (B) is higher than the temperature at the time of coagulation, and The refractive index nDC of the acrylic resin, the refractive index nDA of the diene-based graft copolymer (A), and the refractive index nDB of the hard inelastic polymer (B) satisfy the following expressions (1) and (2). It is characterized by. −0.005 ≦ nDC−nDA ≦ + 0.005 (1) −0.005 ≦ nDC-nDB ≦ + 0.005 (2) The diene-based graft copolymer (A) is rubber-like ( Preferably, the rubber-like (co) polymer contains 60 to 90% by weight of a (co) polymer, and the rubbery (co) polymer is composed of a monomer component containing 1,3-butadiene of 40% by weight or more. The monomer component is
Furthermore, an alkyl acrylate having an alkyl group having 4 to 8 carbon atoms is contained in an amount of 60% by weight or less, and a monofunctional or polyfunctional vinyl monomer which is copolymerizable with the 1,3-butadiene and the alkyl acrylate. It is preferred that the body be contained in a range of not more than 10% by weight. The method for producing an impact resistance modifier for an acrylic resin according to the present invention comprises coagulating both a diene-based graft copolymer (A) latex and a hard inelastic polymer (B) latex to obtain polymer particles. Having a glass transition temperature of the rigid inelastic polymer (B).
Higher than the temperature of the coagulation step, and the refractive index nDC of the acrylic resin, the refractive index nDA of the diene-based graft copolymer (A), and the hard inelastic polymer (B)
Is characterized by satisfying the following expressions (1) and (2). −0.005 ≦ nDC−nDA ≦ + 0.005 (1) −0.005 ≦ nDC-nDB ≦ + 0.005 (2) The acrylic resin composition of the present invention comprises: It is characterized by containing the impact resistance modifier for acrylic resin described in any of the above. The method for modifying the impact resistance of an acrylic resin according to the present invention is characterized in that any one of the above impact modifiers for an acrylic resin is mixed with the acrylic resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The acrylic resin used in the present invention is a transparent resin obtained by polymerizing another monomer copolymerizable therewith with a main component of methyl methacrylate by a known polymerization method,
Preferably, it contains at least 50% by weight of a methyl methacrylate unit. Other monomers include styrene and α-
Methylstyrene, phenyl methacrylate, benzyl methacrylate, alkyl acrylate and the like,
One or more of these can be used in combination. In addition, examples of known polymerization methods include a suspension polymerization method, a bulk polymerization method, and a solution polymerization method, and a production method thereof can be appropriately selected.

The impact modifier for acrylic resin of the present invention is used for modifying the impact resistance of such an acrylic resin, and comprises a diene-based graft copolymer (A) latex. Both the hard inelastic polymer (B) latex and polymer particles obtained by coagulation with a coagulant. The diene-based graft copolymer (A) latex is a latex in which the diene-based graft copolymer (A) is emulsified and dispersed in a liquid, and the diene-based graft copolymer (A)
Is a polymer obtained by graft-polymerizing a monomer that can be polymerized with the rubber-like (co) polymer to a rubber-like (co) polymer as a trunk polymer. In the diene-based graft copolymer (A), the content of the rubbery (co) polymer is 60%.
It is preferably about 90% by weight. If the content of the rubber-like (co) polymer is less than 60% by weight, the impact resistance of the finally obtained impact modifier tends to decrease, while 9
If it exceeds 0% by weight, the powder properties of the finally obtained impact modifier tend to be reduced.

The rubbery (co) polymer, which is the backbone polymer,
It is preferable to be composed of a monomer component containing 40% by weight or more of 1,3-butadiene. When composed of such a monomer component, the impact resistance modifier finally obtained is more excellent in impact resistance imparting ability. The monomer component may be composed of only 1,3-butadiene, and further, an alkyl acrylate having 4 to 8 carbon atoms in an alkyl group may be used.
% Or less, and 10% or less by weight of a monofunctional or polyfunctional vinyl monomer copolymerizable with 1,3-butadiene and an alkyl acrylate.

The alkyl group used here has 4 carbon atoms.
Examples of the alkyl acrylates of Nos. To 8 include alkyl acrylates such as butyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, and allyl acrylate, and one or more of these can be used in combination, but are preferably used. Is butyl acrylate and / or 2-ethylhexyl acrylate. The monofunctional or polyfunctional vinyl monomer copolymerizable with 1,3-butadiene and an alkyl acrylate is not particularly limited, and may be a monofunctional monomer represented by an alkyl methacrylate such as methyl methacrylate. Monomer, divinylbenzene, ethylene glycol dimethacrylate, butylene glycol diacrylate, ethylene glycol diacrylate,
Polyfunctional monomers such as triallyl cyanurate, triallyl isocyanurate, trimethylolpropane triacrylate, and pentaeristol tetraacrylate are used alone or in combination of two or more.

The monomer which is graft-polymerized to the rubber-like (co) polymer, that is, the monomer constituting the graft layer of the diene-based graft copolymer (A) is not particularly limited. Methacrylate, methyl acrylate,
Ethyl acrylate, styrene, α-methylstyrene and the like. Further, it is preferable to determine the monomer composition of the graft layer so as to have the same composition as the acrylic resin whose impact resistance is to be improved. When the resulting impact resistance modifier is mixed with the acrylic resin, the impact resistance can be improved while maintaining high transparency of the acrylic resin.

The polymerization of the rubbery (co) polymer and the graft polymerization of the monomer onto the rubbery (co) polymer are carried out by emulsion polymerization. The emulsifier is not particularly limited, but preferably,
It is an anionic surfactant. Examples of anionic surfactants include carboxylate salts such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate, dipotassium alkenyl succinate; sulfates such as sodium lauryl sulfate; dioctyl sulfosuccinate Sulfonates such as sodium silicate, sodium dodecylbenzenesulfonate and sodium alkyldiphenyl ether disulfonate; and phosphate salts such as sodium polyoxyethylene alkylphenyl ether phosphate. The diene-based graft copolymer (A) latex can be obtained by performing the polymerization of the rubber-like (co) polymer and the graft polymerization of the monomer onto the rubber-like (co) polymer by emulsion polymerization.

The impact resistance modifier for acrylic resin of the present invention includes a refractive index of the diene graft copolymer (A) in the diene graft copolymer (A) latex thus obtained. Those having nDA satisfying the following expression (1) are used. In the formula (1), nDC is the refractive index of the acrylic resin in which the impact modifier is blended. −0.005 ≦ nDC−nDA ≦ + 0.005 (1) The impact resistance modifier obtained from the diene-based graft copolymer (A) having a refractive index that satisfies such conditions is used as an acrylic resin. When blended, impact resistance can be imparted to the acrylic resin while maintaining transparency. In particular, it is preferable that the refractive index nDA1 of the rubbery (co) polymer as the trunk polymer and the refractive index nDA2 of the graft layer grafted thereon satisfy the following formulas (3) and (4), respectively. . −0.005 ≦ nDC−nDA1 ≦ + 0.005 (3) −0.005 ≦ nDC−nDA2 ≦ + 0.005 (4) The refractive indices nDA1 and nDA2 are calculated by the above formula (3).
When satisfying (4), an acrylic resin composition having more excellent transparency can be obtained.

The refractive index in the present invention refers to the ratio of the propagation speed of the wavefront of light in a vacuum to the wavefront of light in a polymer. The refractive index can be determined by measurement using a refractometer, but can also be calculated from the charged weight ratio of the homopolymer of each monomer component contained in the polymer and the refractive index as follows. For example, the refractive index of the polymer is nDα, and xa, xb, xc,..., Xm are the weight fractions of the monomers a, b, c,..., M contained in the polymer, respectively, and nDa, nDb, nDc, ..., nDm
Are the homopolymers a, b, c,..., M of the above-mentioned monomers contained in the polymer, respectively,
It can be calculated by equation (5). nDα = xanDa + xbnDb + xcnDc + ... + xcnDm (5) (however, xa + xb + xc + ... + xm = 1)

Next, the hard inelastic polymer (B) latex will be described. The rigid inelastic polymer (B) latex is a latex in which a rigid inelastic polymer (B) having no double bond in a molecule is emulsified and dispersed in a liquid, and is composed of acrylate, methacrylate, aromatic It is obtained by emulsion polymerization of one or more monomers such as vinyl and vinyl cyanide compounds in combination.
In the present invention, the rigid inelastic polymer (B) has a glass transition temperature higher than the temperature of the coagulation step described later, and has a refractive index nDB satisfying the following formula (2). Need to be something. −0.005 ≦ nDC−nDB ≦ + 0.005 (2) Glass transition temperature and refractive index nD of the rigid inelastic polymer (B)
When B 2 satisfies such conditions, the resulting impact resistance modifier has excellent powder properties such as blocking resistance and bulk density, and is mixed with an acrylic resin to form a molded product. , The transparency does not decrease.

Therefore, the composition of the monomer constituting the rigid inelastic polymer (B) is appropriately determined so that the glass transition temperature and the refractive index nDB of the rigid inelastic polymer (B) satisfy such conditions. Selected. Examples of the monomer include methyl methacrylate, ethyl methacrylate, and butyl methacrylate as methacrylates, styrene and α-methylstyrene as aromatic vinyls, and methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl as acrylates. Examples of acrylates and the like include acrylonitrile and methacrylonitrile as vinyl cyanide compounds. In order to improve compatibility with the acrylic resin, methyl methacrylate is preferably used as a main component, that is, 50% by weight or more. The glass transition temperature and the refractive index of the resulting rigid inelastic polymer (B) can be adjusted by appropriately adjusting the amount of a monomer such as acrylate or styrene.

For example, when the temperature in the coagulation step described later is 60 ° C. and the refractive index of the acrylic resin containing the impact resistance modifier is 1.490, the hard inelastic polymer ( As B), methyl methacrylate 82.5
What consists of weight%, 13.5 weight% of butyl acrylate, and 4.0 weight% of styrene is preferable. The hard inelastic polymer (B) thus obtained has a glass transition temperature of 7
1 ° C., the refractive index is 1.491, which satisfies the above expression (2), and has a higher glass transition temperature than the temperature in the coagulation step. Therefore, the impact resistance modifier obtained by using this hard inelastic polymer (B) imparts impact resistance to the acrylic resin having a refractive index of 1.490 while maintaining the transparency thereof. it can. The emulsifier used for the polymerization of the rigid inelastic polymer is not particularly limited, but it is preferable to use the same emulsifier used for the polymerization of the diene-based graft copolymer (A). Further, as the polymerization initiator and other auxiliaries, any one can be used as long as it can be used for emulsion polymerization.

The glass transition temperature of the hard inelastic polymer (B) is not limited as long as it is higher than the temperature of the coagulation step described later, but is preferably 5 to 40 ° C. higher than the temperature of the coagulation step. Further, it is preferable that the temperature is higher by 10 to 30 ° C. than the temperature of the coagulation step. When the glass transition temperature of the rigid inelastic polymer (B) is in such a range, an impact resistance modifier having more excellent powder properties such as blocking resistance and bulk density can be obtained. As a method of determining the glass transition temperature, it can be measured using a glass transition temperature measuring device, but the charged weight ratio of the monomers contained in the polymer, and the glass transition of the homopolymer composed of each monomer It can also be calculated from the temperature using the Fox equation. For example, the glass transition temperature of the polymer is Tg, the weight ratio of the monomer components is W1, W2,
.., Wn, and the glass transition temperatures of the homopolymers are Tg1, Tg2, Tg3,... Tn, which can be calculated by the following equation (6). 1 / Tg = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 + ... + Wn / Tgn (6) (W1 + W2 + W3 + ... + Wn = 1.0)

The diene-based graft copolymer (A) latex and the hard inelastic polymer (B) obtained as described above
By performing a coagulation step of coagulating the latex with a coagulant together with the coagulant, polymer particles as the impact modifier of the present invention can be produced. In the coagulation step, a hard inelastic polymer (B) having a glass transition temperature higher than the temperature of the coagulation step, that is, a coagulation temperature, is used. After the coagulation step, a solidification step for promoting secondary aggregation is usually performed. The specific method of performing the coagulation step is not particularly limited. For example, a continuous stirring tank in which three stirring tanks provided with stirring blades such as a three-way sweeping blade, a propeller blade, a turbine blade, a paddle blade, and a disk blade are continuous. Use the first
When the tank is used as a coagulation tank for coagulation, and the second and subsequent tanks are used as solidification tanks for solidification, the coagulation step and the solidification step can be performed continuously, which is preferable in terms of productivity and equipment costs. . Then, the diene graft copolymer (A) is added to the coagulation tank.
Latex, rigid inelastic polymer (B) latex,
A coagulant solution is added to each, and they are brought into contact in a stirring tank to perform coagulation. As a method of adding these to the coagulation tank, for example, only the coagulant solution is supplied in advance to the coagulation tank, and the diene graft copolymer (A) latex and the hard inelastic polymer (B ) And a method of continuously adding a latex, respectively, a coagulant solution, a diene-based graft copolymer (A) latex, and a hard inelastic polymer (B) latex are simultaneously and continuously added to a coagulation tank. Method. Examples of the addition method include a method in which a nozzle is immersed in a coagulation tank and installed, and the nozzle is continuously discharged from the nozzle, a method in which the nozzle is dropped from above the tank, and the like.

When a hard inelastic polymer (B) having a glass transition temperature higher than the coagulation temperature is used, the hard inelastic polymer (B) is hard and brittle in a glassy state in the coagulation step. It is easily destroyed. Therefore, the hard non-elastic polymer (B) latex comes into contact with the coagulant while being stirred and coagulates, whereby the hard non-elastic polymer (B) particles coagulate and coagulate due to the shear force of the stirring blade. Particles are finely broken. As a result, the particles of the hard inelastic polymer (B) become fine particles and densely cover around the coagulated diene-based graft copolymer (A) particles. Then, in the subsequent solidification step, the diene-based graft copolymer (A) particles themselves are solidified, and the surrounding hard inelastic polymer (B) particles adhere to the diene-based graft copolymer (A) particles. Thus, a coating layer is formed. Thus, the hard inelastic polymer (B)
When a coagulation particle is used while having a glass transition temperature higher than the temperature of the coagulation step and coagulation is carried out with stirring, the agglomerated particles are finely broken by the shearing force of the stirring blade, and this is a diene graft copolymer (A). ) The particles are densely and strongly covered around the particles. As a result, the diene-based graft copolymer (A) particles have suppressed bulking and excellent bulk density. Further, by further performing the solidification step under a temperature condition higher than the glass transition temperature of the rigid inelastic polymer (B), the diene-based graft copolymer (A) has a stronger rigid inelastic polymer (B) on the particle surface.
Can be fixed.

The temperature of the coagulation step is not particularly limited as long as it is a temperature at which the polymer latex coagulates.
８０80 ° C. If the temperature is lower than 30 ° C., the coagulation may not proceed sufficiently. If the temperature exceeds 80 ° C., the coarse powder tends to increase. The temperature of the solidification step is preferably 10 to 30 ° C. higher than the glass transition temperature of the rigid inelastic polymer (B). By performing the solidification step at such a temperature, the fixation of the hard inelastic polymer (B) to the diene-based graft copolymer (A) particles proceeds more. In addition, even if the solidification step is performed in one stage operating at a constant temperature, the temperature is increased stepwise.
Although the solidification may be performed in two or more stages, it is preferable to perform the solidification in two or more stages because solidification proceeds more reliably. In the coagulation step, the ratio of the diene-based graft copolymer (A) and the hard inelastic polymer (B) is such that the solid content weight is such that the hard-elastic polymer (A) It is preferable that the inelastic polymer (B) is 1.0 to 5.0 parts by weight. When the amount of the hard inelastic polymer (B) is less than 1.0 part by weight, coating on the surface of the diene-based graft copolymer (A) particles becomes insufficient, and the bulk density and blocking resistance of the polymer particles are sufficiently improved. If the amount exceeds 5.0 parts by weight, a large amount of fine powder is generated in the coagulation step, which leads to deterioration of powder properties such as deterioration of handling properties due to dusting.

The coagulant used in the coagulation step differs depending on the emulsifier used in the diene-based graft copolymer (A) latex and the hard inelastic polymer (B) latex. When the emulsifier used for these is a weak acid salt such as a carboxylate, an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid or an inorganic salt such as calcium chloride, magnesium sulfate or aluminum sulfate is used as a coagulant; calcium acetate And organic acid salts such as aluminum acetate, and the like, and preferably an inorganic acid. When a strong acid salt such as a sulfate ester salt is used as an emulsifier in at least one of the diene-based graft copolymer (A) latex and the hard inelastic polymer (B) latex, the coagulant is used as a coagulant. Are inorganic salts such as calcium chloride, magnesium sulfate, and aluminum sulfate; calcium acetate,
It is preferable to use an organic acid salt such as aluminum acetate. The coagulant is used in an amount sufficient to rapidly solidify the polymer particles, and the amount depends on the type of coagulant,
Although it depends on the type and content of the emulsifier in the diene-based graft copolymer (A) latex and the hard inelastic polymer (B) latex, it is usually 0.5% by weight or more based on the polymer particles, It is preferably at least 1.0% by weight. If the use amount of the coagulant is less than 0.5% by weight, the polymer particles cannot be sufficiently coagulated, the water content of the obtained polymer particles increases, and the productivity in the subsequent drying step is reduced. Tends to decrease.

After performing the coagulation step and the solidification step,
The obtained slurry is centrifugally dehydrated and dried to obtain polymer particles. By blending the polymer particles as an impact modifier in an amount of 10 to 40 parts by weight based on 100 parts by weight of the acrylic resin, the impact resistance of the acrylic resin can be modified. The acrylic resin composition thus obtained is formed into a molded product such as a lighting fixture, a signboard, various building materials, and a sound insulating plate by a known method. In addition, known additives such as a stabilizer and an ultraviolet absorber may be added to the acrylic resin composition as necessary. A molded article of such an acrylic resin composition has sufficiently excellent impact resistance and maintains transparency, and can be used for a wide range of applications.

[0025]

EXAMPLES In the examples, "parts" and "%" represent "parts by weight" and "% by weight", respectively. Various physical properties were measured by the following methods. [Particle size distribution] The particle size distribution was measured using an evaluation device defined by Japanese Industrial Standards (JIS No. 408). [Glass transition temperature (Tg)] The glass transition temperature (Tg) was calculated by the above formula (6) using the charged weight ratio and the Tg of the homopolymer of each monomer component contained in the hard inelastic polymer (B). [Refractive index] Using the refractive index and charge ratio of the homopolymer of each monomer component contained in the diene-based graft copolymer (A), the rigid inelastic polymer (B), and the acrylic resin (C), It was calculated by equation (5). [Bulk specific gravity] The bulk specific gravity of the polymer particles was measured according to JIS-K-672.
1 was performed. (Unit: g / cm ³ ) [Blocking resistance] 20 g of polymer particles were placed in a cylindrical container, and a pressure of 0.7 kg / cm ² was applied at 50 ° C. for 2 hours. Vibration was applied to the obtained block with a micro-type electromagnetic vibration sieve (manufactured by Tsutsui Rika), and the time (second) for breaking the block by 60% was measured. [Evaluation of Transparency] An acrylic resin and an impact modifier composed of polymer particles were melt-kneaded, injection-molded, and the transparency of the obtained molded plate was visually evaluated in five steps. The abbreviations in the table indicate the following contents. : Extremely good ○: fairly good △: good ×: bad XX: extremely bad

[Example 1] [Preparation of rubber-like polymer [1]]
The mixture was charged in an autoclave and emulsion-polymerized at 50 ° C. for 9 hours. Among the following substances, for substances other than 1,3-butadiene, oxygen contained therein was replaced with nitrogen before the start of polymerization, so that the polymerization reaction was not substantially inhibited. As a result, the conversion was 97% and the average particle size was 0.9 μm.
A latex of the rubbery polymer [1] was obtained. Butyl acrylate 5.5 kg 1,3-butadiene 4.5 kg Diisopropylbenzene hydroperoxide 20 g Potassium tallow fatty acid 100 g Sodium N-lauroyl sarcosinate 50 g Sodium pyrophosphate 50 g Ferrous sulfate 0.5 g Dextrose 30 g Deionized water 20 kg

[Preparation of Acid Group-Containing Copolymer (E)] A mixture having the following composition was placed in a 5 L glass round bottom flask,
Polymerization was performed at 1.5 ° C. for 1.5 hours (first stage polymerization). Butyl acrylate 250 g Potassium oleate 20 g Dioctyl sodium sulfosuccinate 10 g Cumene hydroperoxide 10 g Sodium formaldehyde sulfoxylate 3 g Deionized water 2000 g Subsequently, a mixture having the following composition was added dropwise at 70 ° C. over 1 hour, and then stirred for 1 hour. Subsequently, polymerization was performed (second-stage polymerization) to obtain a latex of the acid group-containing copolymer (E). The conversion was 98%. Butyl acrylate 600 g Methacrylic acid 150 g Cumene hydroperoxide 3 g

[Preparation of enlarged rubbery polymer [2]] 60 L
In an autoclave, 300 g of the latex of the acid group-containing copolymer (E) obtained above was stirred while the latex of the rubbery polymer [1] (including 10 kg of polymer solid content) was stirred at an internal temperature of 30 ° C. In addition, then hold for 30 minutes,
An enlarged rubbery polymer latex having an average particle diameter of 0.132 μm was obtained. Thereafter, 340 g of a 10% aqueous sodium sulfate solution was added while stirring at an internal temperature of 50 ° C., and the mixture was maintained for 15 minutes to obtain a latex of an enlarged rubber-like polymer [2] having an average particle diameter of 0.148 μm.

[Graft polymerization of enlarged rubber-like polymer [2]] To the latex of the above-described enlarged rubber-like polymer [2],
The following substances were added in a lump in order and kept for 60 minutes. Then, the internal temperature was raised to 80 ° C. and kept for 1 hour to obtain a latex of a diene-based graft copolymer [3]. Deionized water 500 g Disodium ethylenediaminetetraacetate 0.012 g Ferrous sulfate 0.004 g Sodium formaldehyde sulfoxylate 15.0 g Deionized water 2400 g Then, the following mixture of deionized water was added at once and then 15 minutes Held. 50 g of sodium N-lauroyl sarcosinate 1000 g of deionized water Next, a monomer-containing mixture having the following composition was added over 60 minutes, and then polymerization was further continued for 60 minutes to obtain a diene-based graft copolymer [ 3] was obtained. At that time, the conversion of methyl methacrylate was 99%. Methyl methacrylate 3.8 kg Methyl acrylate 0.16 kg Normal octyl mercaptan 20 g t-butyhydroperoxide 6.0 g Next, under the temperature condition of 50 ° C., the butadiene copolymer [3] obtained above was subjected to The following mixture was added with stirring. 2,2 'methylenebis (4-methyl-6-t-butylphenol) 30 g Potassium tallow fatty acid 20 g Deionized water 400 g After that, the internal temperature was kept at 40 ° C or less, and the diene graft copolymer [3] was obtained from a 60 L autoclave. Latex (35.6% solids) was removed.

[Preparation of rigid inelastic polymer (P1) latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenyl succinate, 0.02 part of n-octyl mercaptan, 82.6 parts of methyl methacrylate, and 3 parts of styrene. 4 copies,
14 parts of butyl acrylate and 260 parts of water were charged, and 0.15 part of potassium persulfate was added, followed by polymerization at 60 ° C. for 2 hours. Further, 0.1 part of t-butyl hydroperoxide and 0.12 part of formaldehyde sodium sulfoxylate were added and polymerized at 62 ° C. for 2 hours,
Hard inelastic polymer (P1) latex (Tg = 70 ° C.)
Refractive index: 1.490).

[Coagulation Process] This was carried out in three tanks in which two 5.0 L overflow (stirring tanks) were connected in series downstream of a 3.6 L overflow stirring tank (coagulation tank). .
In addition, a three-way swept wing was used as the stirring wing. An immersion nozzle for supplying the diene graft copolymer [3] was provided in the coagulation tank from the top of the tank at a position of 45 degrees clockwise (in the same direction as the stirring rotation direction) starting from the overflow port. The immersion nozzle was immersed perpendicular to the liquid surface, and was set such that the depth of the discharge port was 50 mm from the liquid surface. At this time, the direction of the discharge port was set so that the discharge direction was the direction of the main flow direction in the stirring tank. Then, the coagulant aqueous solution supply position is set at an angle of 180 degrees clockwise from the overflow port as a starting point, and the rigid inelastic polymer (P1) is used.
The latex supply position was set at a position of 90 degrees and a position separated by 50 mm from the wall surface. 0.48 for coagulant
% Sulfuric acid aqueous solution, the temperature of each tank was set to coagulation tank / solidification 1 tank / solidification 2 tank = 60/70/88 ° C. 365, 365,
It was set to 324 rpm. Then, 6.6 kg / hr of the diene-based graft copolymer [3] was injected from the immersion nozzle,
7.26 kg / hr of a 0.48% sulfuric acid aqueous solution [latex / sulfuric acid = 1 / 1.1 (polymer solid concentration 2 in coagulation tank)
2.2%)], and 0.313 kg of a rigid inelastic polymer (P1) latex further diluted to a solid concentration of 14%.
/ Hr (2 parts in terms of solid content with respect to 100 parts of graft copolymer), the addition rate was set, and each was continuously and independently added into a coagulation tank to perform continuous coagulation. After the steady state, the coagulation liquid slurry was sampled from the outlet of the final tank. Under these coagulation conditions, the amount of coagulant was 10
The amount was 1.1 parts with respect to 0 parts, and the actually measured pH in the coagulation tank was 1.6.

[Recovery of Polymer Particles] The obtained coagulation liquid slurry was subjected to dehydration treatment (1800 rpm: 3 minutes) by a centrifugal dehydrator (Tanabe upper discharge type O-20), and then hot air temperature of 8
The polymer particles (impact modifier) were dried using a batch-type fluidized drier set at 0 ° C. The bulk ratio and blocking resistance were measured. Table 1 shows the results.

[Acrylic resin composition] 2.8 kg of the obtained polymer particles (impact modifier) and a transparent acrylic resin (Acrypet VH (refractive index: 1.491, manufactured by Mitsubishi Rayon Co., Ltd.)) 7.2 kg, 10 g of monoglyceride stearate, 20 g of an ultraviolet absorber (Tinuvin P manufactured by Ciba-Gaiky), 30 g of an ultraviolet absorber (Sanol LS770 manufactured by Sankyo Co., Ltd.), and a phosphorus-based stabilizer (Asahi Denka Co., Ltd.)
2112) and 20 g of a hindered phenol-based stabilizer (AO60 manufactured by Asahi Denka Co., Ltd.)
The acrylic resin composition obtained by mixing for 5 minutes with a Henschel mixer having a capacity of 0 L was then used for a 230-mm twin screw extruder (PCM-30 manufactured by Ikegai Iron Works Co., Ltd.) to obtain 230-300 mm.
The pellet was formed at a temperature of 250 ° C. and a rotation speed of 250 rpm. Using a screw-type injection molding machine (IS-22PN manufactured by Toshiba), the pellet-shaped resin was used at a cylinder temperature of 250 ° C. and an injection pressure (gauge pressure) of 50 kg / cm ² to obtain 110 × 110 × 3 (thickness). mm and 70 × 12.5
× 6.2 (thickness) mm test pieces were prepared. Table 1 shows the results of visual evaluation of the transparency of the obtained pellets. Further, the refractive index of the acrylic resin, the refractive index of the diene-based graft copolymer [3], the refractive index of the hard inelastic polymer (P1),
Table 1 also shows the glass transition temperature of the rigid inelastic polymer (P1).
Shown in

Example 2 Example 1 was repeated except that the following rigid inelastic polymer (P2) was used as the rigid inelastic polymer.
In the same manner as in the above, polymer particles (impact modifier) and an acrylic resin composition were prepared and evaluated. Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P2) latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenylsuccinate and n
-0.02 part of octyl mercaptan, 87.8 parts of methyl methacrylate, 2.4 parts of styrene, 9.8 parts of butyl acrylate and 260 parts of water were added, and 0.15 part of potassium persulfate was added thereto. The polymerization was carried out for 2 hours.
Further, 0.1 part of t-butyl hydroperoxide and 0.12 formaldehyde sodium sulfoxylate were added.
The polymerization was conducted at 62 ° C. for 2 hours to obtain a hard inelastic polymer latex (Tg = 80 ° C., refractive index: 1.490).

Example 3 Example 1 was repeated except that the following rigid inelastic polymer (P2) was used as the rigid inelastic polymer.
In the same manner as in the above, polymer particles (impact modifier) and an acrylic resin composition were prepared and evaluated. Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P3) latex] In a reaction vessel equipped with a stirrer, 0.15 parts of potassium persulfate, 0.03 part of n-octylmercaptan, 1 part of dipotassium alkenylsuccinate, 80 parts of methyl methacrylate, and ethyl 20 parts of acrylate and 260 parts of water were charged and polymerized at 69 ° C. for 2 hours to obtain a hard inelastic polymer latex (T
g = 71 ° C. Refractive index: 1.486).

Comparative Example 1 Polymer particles and an acrylic resin composition were prepared and evaluated in the same manner as in Example 1 except that the hard inelastic polymer (P1) was not used. Table 1 shows the evaluation results.

[Comparative Example 2] In the same manner as in Example 1 except that the temperature at the time of coagulation in the solidification process was 70 ° C and the following hard inelastic polymer (P4) was used as the hard inelastic polymer, Polymer particles and an acrylic resin composition were prepared and evaluated. Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P4) latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenylsuccinate and n
-0.02 part of octyl mercaptan, 80.9 parts of methyl methacrylate, 0.5 part of styrene, 18.6 parts of butyl acrylate and 260 parts of water are added, and 0.15 part of potassium persulfate is added thereto. The polymerization was carried out for 2 hours. Further, t-butyl hydroperoxide was added to 0.1%.
Part and formaldehyde sodium sulfoxylate 0.
12 parts were added and polymerization was carried out at 62 ° C. for 2 hours. A hard inelastic polymer latex (Tg = 60 ° C., refractive index: 1.48)
6) got

Comparative Example 3 Polymer particles and an acrylic resin composition were prepared and evaluated in the same manner as in Example 1 except that the following hard inelastic polymer (P5) was used as the hard inelastic polymer. . Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P5) latex] N-lauroyl sarcosine sodium was added to a reaction vessel equipped with a stirrer.
And 0.02 part of n-octyl mercaptan, 50 parts of methyl methacrylate, 40 parts of styrene, 10 parts of butyl acrylate and 260 parts of water, and 0.15 part of potassium persulfate was added, followed by polymerization at 60 ° C. for 2 hours. I let it. Further, 0.1 part of t-butyl hydroperoxide and 0.12 part of formaldehyde sodium sulfoxylate were added and polymerized at 62 ° C. for 2 hours to obtain a hard inelastic polymer (P5) latex (Tg = 80 ° C. : 1.52
8) was obtained.

Comparative Example 4 Polymer particles and an acrylic resin composition were prepared and evaluated in the same manner as in Example 1 except that the following hard inelastic polymer (P6) was used as the hard inelastic polymer. . Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P6) latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenylsuccinate and n
-0.02 part of octyl mercaptan, 55 parts of methyl methacrylate, 40 parts of styrene, 5 parts of butyl acrylate and 260 parts of water were charged, and potassium persulfate was added in an amount of 0.1 part.
15 parts were added and polymerized at 60 ° C. for 2 hours. Furthermore, t-
0.1 part of butyl hydroperoxide and 0.12 part of formaldehyde sodium sulfoxylate were added and polymerized at 62 ° C. for 2 hours to obtain a hard inelastic polymer latex (Tg = 90 ° C., refractive index: 1.529). Obtained.

[Example 4] [Preparation of rubbery polymer [1 '] All the following substances were charged into a 40 L autoclave, and 5
Emulsion polymerization was carried out at 0 ° C. for 9 hours. In addition, among the following substances, except for 1,3-butadiene, the oxygen contained therein was replaced with nitrogen before the start of the polymerization, so that the polymerization reaction was not substantially inhibited. As a result, the conversion rate is 97%
As a result, a latex of a rubbery polymer [1 ′] having an average particle size of 0.9 μm was obtained. Butyl acrylate 1.0 kg 1,3-butadiene 9.0 kg Diisopropylbenzene hydroperoxide 20 g Potassium tallow fatty acid 100 g Sodium N-lauroyl sarcosinate 50 g Sodium pyrophosphate 50 g Ferrous sulfate 0.5 g Dextrose 30 g Deionized water 20 kg

[Preparation of Enlarged Rubbery Polymer [2 ']] 60
In an L autoclave, a latex of rubber-like polymer [1 '] (containing 10 kg of polymer solid content) was heated at an internal temperature of 30 ° C.
While stirring, 300 g of the latex of the acid group-containing copolymer (A) was added, and the mixture was held for 30 minutes to obtain a latex of an enlarged rubbery polymer having an average particle diameter of 0.132 μm. Then, 10% while stirring at an internal temperature of 50 ° C.
A 340 g portion of an aqueous solution of sodium sulfate was added, and the mixture was kept for 15 minutes to obtain a latex of an enlarged rubber-like polymer [2 ′] having an average particle diameter of 0.148 μm.

[Graft polymerization of the enlarged rubber-like polymer [2 ']] The following substances were added to the latex of the above-mentioned enlarged rubber-like polymer [2'] in a lump in order and held for 60 minutes.
Thereafter, the internal temperature was raised to 80 ° C. and maintained for 1 hour to obtain a latex of a diene-based graft copolymer [3 ′]. Deionized water 500 g Disodium ethylenediaminetetraacetate 0.012 g Ferrous sulfate 0.004 g Sodium formaldehyde sulfoxylate 15.0 g Deionized water 2400 g Next, a monomer-containing mixture having the following composition is added over 60 minutes. Thereafter, polymerization was continued for further 60 minutes to obtain a latex of a diene-based graft copolymer [3 '].
At that time, the conversion of methyl methacrylate was 99%. Methyl methacrylate 3.0 kg Styrene 1.0 kg Normal octyl mercaptan 20 g t-butyl hydroperoxide 6.0 g Next, the following mixture was stirred with a latex of the diene-based graft copolymer at a temperature of 50 ° C. added. 2,2 'methylenebis (4-methyl-6-t-butylphenol) 30 g Potassium tallow fatty acid 20 g Deionized water 400 g Then, a latex of diene-based graft copolymer (solid 35.6%).

[Preparation of Hard Inelastic Polymer (P7) Latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenylsuccinate, 0.02 part of n-octylmercaptan, 67 parts of methyl methacrylate, 24 parts of styrene, 24 parts of butyl 9 parts of acrylate and 260 parts of water were charged, and 0.15 part of potassium persulfate was added, followed by polymerization at 60 ° C. for 2 hours. Further, t-butyl hydroperoxide was added to 0.1%.
Part and formaldehyde sodium sulfoxylate 0.
12 parts were added and polymerization was carried out at 62 ° C. for 2 hours. A hard inelastic polymer latex (Tg = 80 ° C., refractive index: 1.51)
2) was obtained. [Coagulation process and acrylic resin composition] The coagulation process was performed in the same manner as in Example 1 to obtain polymer particles (impact modifier). Then, as an acrylic resin, a methyl methacrylate-styrene copolymer (refractive index: 75% by weight of methyl methacrylate and 25% by weight of styrene)
An acrylic resin composition was prepared and evaluated in the same manner as in Example 1 except that 1.515) was used. Table 1 shows the evaluation results.

Comparative Example 5 Polymer particles were prepared in the same manner as in Example 1 except that the diene-based graft copolymer (3 ') prepared in Example 4 and the hard inelastic polymer (P7) were used. (Impact modifier) and an acrylic resin composition were prepared and evaluated. Table 1 shows the evaluation results.

Comparative Example 6 Polymer particles (impact modifier) and an acrylic resin composition were prepared and evaluated in the same manner as in Example 1 except that the acrylic resin prepared in Example 4 was used. did. Table 1 shows the evaluation results.

Comparative Example 7 Polymer particles (impact modifier) and acrylic resin were prepared in the same manner as in Example 1 except that the following rigid inelastic polymer (P8) was used as the rigid inelastic polymer. A resin composition was prepared and evaluated. Table 1 shows the evaluation results. [Preparation of rigid inelastic polymer (P8) latex] In a reaction vessel equipped with a stirrer, 1 part of dipotassium alkenyl succinate and n-
0.02 parts of octyl mercaptan, 58.2 parts of methyl methacrylate, 8.1 parts of styrene, 33.7 parts of butyl acrylate and 260 parts of water were charged, and 0.15 part of potassium persulfate was added. Polymerized for hours.
Further, 0.1 part of t-butyl hydroperoxide and 0.12 formaldehyde sodium sulfoxylate were added.
Then, polymerization was carried out at 62 ° C. for 2 hours, and a hard inelastic polymer (P8) latex (Tg = 30 ° C., refractive index: 1.4)
90).

[0047]

[Table 1]

As is clear from Table 1, the impact modifiers obtained in Examples 1 to 4 all include a hard inelastic polymer having a glass transition temperature higher than the temperature at the time of coagulation. As a result, the powder had high bulk specific gravity, good blocking resistance, and excellent powder properties. Then, the refractive indices of the diene-based graft copolymer and the hard inelastic polymer in the impact modifier and the acrylic resin containing the impact modifier are represented by the above formulas (1) and (2). Since it satisfied, the acrylic resin composition was also very excellent in transparency. On the other hand, the acrylic resin composition of Comparative Example 1 to which an impact resistance modifier that does not use a rigid inelastic polymer was added was excellent in transparency, but the bulk specific gravity of the impact resistance modifier was low. The blocking resistance was very poor, and the workability was poor. In Comparative Examples 2 and 7, since the glass transition temperature of the hard inelastic polymer used for the impact modifier was low, the powder properties were also insufficient. In Comparative Examples 3 to 6, the powder properties of the impact modifier used were excellent, but the refractive index of each component did not satisfy the above formulas (1) and / or (2). The properties were poor.

[0049]

As described above, the impact modifier for acrylic resin of the present invention coagulates both the diene graft copolymer (A) latex and the hard inelastic polymer (B) latex. The hard inelastic polymer (B) has a glass transition temperature higher than the temperature at the time of coagulation and a refractive index nDC of the acrylic resin.
And the refractive index nD of the diene-based graft copolymer (A)
Since A and the refractive index nDB of the hard inelastic polymer (B) satisfy a specific relationship, they have excellent impact resistance-imparting ability, good bulk specific gravity, good blocking resistance, and The acrylic resin composition is also excellent in transparency.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4J002 BC03X BC09X BG06X BG10X BN14W 4J026 AA18 AA45 AA46 AA61 AA68 AC18 AC34 AC36 BA05 BA27 CA08

Claims (8)

[Claims] An impact modifier incorporated in an acrylic resin, wherein the diene-based graft copolymer (A) latex and the hard inelastic polymer (B) latex are coagulated together. The hard inelastic polymer (B) has a glass transition temperature higher than the temperature at the time of coagulation, and has a refractive index nDC of the acrylic resin and the diene-based graft copolymer (A). The impact resistance modifier for acrylic resin, wherein the refractive index nDA and the refractive index nDB of the hard inelastic polymer (B) satisfy the following formulas (1) and (2). -0.005≤nDC-nDA≤ + 0.005 ... (1) -0.005≤nDC-nDB≤ + 0.005 ... (2) 2. The diene-based graft copolymer (A) contains 60 to 90% by weight of a rubbery (co) polymer, and the rubbery (co) polymer contains 1,3-butadiene in an amount of 40 to 90% by weight.
The impact modifier for acrylic resin according to claim 1, comprising a monomer component containing not less than% by weight. 3. The monomer component further comprises 60% by weight of an alkyl acrylate having 4 to 8 carbon atoms in the alkyl group.
3. A monofunctional or polyfunctional vinyl monomer copolymerizable with the 1,3-butadiene and the alkyl acrylate in an amount of 10% by weight or less. The impact modifier for acrylic resin according to 1. 4. A method for producing an impact modifier incorporated in an acrylic resin, comprising coagulating both a diene-based graft copolymer (A) latex and a hard inelastic polymer (B) latex. The hard inelastic polymer (B) has a glass transition temperature higher than the temperature of the coagulation step, and the refractive index nDC of the acrylic resin and the diene -Based graft copolymer (A)
And a refractive index nDB of the hard inelastic polymer (B) satisfies the following formulas (1) and (2). -0.005≤nDC-nDA≤ + 0.005 ... (1) -0.005≤nDC-nDB≤ + 0.005 ... (2) 5. The diene-based graft copolymer (A) contains 60 to 90% by weight of a rubbery (co) polymer, and the rubbery (co) polymer contains 1,3-butadiene in an amount of 40 to 90% by weight.
The method for producing an impact resistance modifier for an acrylic resin according to claim 4, wherein the method comprises a monomer component containing at least% by weight. 6. The monomer component further comprises 60% by weight of an alkyl acrylate having 4 to 8 carbon atoms in the alkyl group.
The monofunctional or polyfunctional vinyl monomer copolymerizable with the 1,3-butadiene and the alkyl acrylate in an amount of 10% by weight or less. The method for producing an impact resistance modifier for an acrylic resin according to the above. 7. An acrylic resin composition comprising an acrylic resin and the impact modifier for acrylic resin according to claim 1. Description: 8. A method for modifying the impact resistance of an acrylic resin, comprising blending the acrylic resin with the impact modifier for an acrylic resin according to any one of claims 1 to 3.