JPH0522735B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a crosslinked latex composition containing an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer as a main component. , weather resistance,
The present invention relates to a crosslinked latex composition suitable for producing a thermoplastic resin having excellent impact resistance and surface gloss. Prior art Weather resistance and resistance are improved by graft polymerizing an alkenyl aromatic compound and a vinyl monomer copolymerizable with the alkenyl aromatic compound to ethylene/α-olefin copolymer rubber or ethylene/α-olefin/polyene copolymer rubber. Several attempts have been made to obtain thermoplastic resins with excellent impact resistance, surface gloss, and the like. For example, Japanese Patent Publication No. 43-16394 discloses that the rubber component is made into a latex state and gelled in the presence of a crosslinking monomer such as divinylbenzene.
A method for obtaining a thermoplastic resin by subsequent graft copolymerization is disclosed, and
No. 48-35718 discloses a method in which the rubber particles in latex are swollen with liquid aliphatic hydrocarbon or alicyclic hydrocarbon, and graft copolymerization is carried out in this state. However, in the known prior art, it has not been possible to obtain a thermoplastic graft copolymer resin having a practically usable level of weather resistance, impact resistance, surface gloss, etc., by any of the methods. Summary of the Invention The present inventors have developed a crosslinked latex composition having an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer as a base polymer. When graft copolymerizing an alkenyl aromatic compound and a vinyl monomer using a composition in which the diameter and the hot toluene insoluble content (gel %) of the polymer component are within a specific range as a starting material, the above-mentioned properties can be achieved. It has been found that an extremely excellent thermoplastic resin can be obtained. OBJECTS OF THE INVENTION An object of the present invention is to provide a crosslinked latex composition that is particularly useful for producing thermoplastic graft copolymer resins having excellent properties such as weather resistance, impact resistance, and surface gloss. Another object of the present invention is to provide a crosslinked latex composition having an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer as a base polymer, which itself has excellent storage stability. is to provide. Structure of the Invention According to the present invention, an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene having an intrinsic viscosity in a decahydronaphthalene solution at 135° C. in the range of 0.5 to 2.0 dl/g. An unsaturated carboxylic acid compound modified product of an amorphous copolymer and a crystalline low molecular weight α-olefin copolymer having a density of 0.90 g/cm 3 or more and 2 to 50 parts by weight per ¹⁰⁰ parts by weight of the amorphous copolymer. A crosslinked latex composition in which crosslinking bonds are formed using a polyfunctional monomer as a crosslinking aid, and the average particle size of the solid content is 0.2 to 0.2.
A crosslinked latex composition for a thermoplastic graft copolymer resin, characterized in that the amorphous copolymer component has a diameter of 3.0 μm and a hot toluene insoluble content of the amorphous copolymer component of 30 to 95% by weight. is provided. Preferred embodiment of the invention Amorphous copolymer component In the present invention, an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer is used as the base polymer in the latex. do. In this specification, the term "amorphous copolymer" refers not only to completely amorphous copolymers such as so-called rubber, but also to low-crystalline copolymers with a crystallinity of 15% or less as measured by X-ray diffraction. It also includes polymers of various degrees. The α-olefin constituting such an amorphous copolymer includes α-olefin having 3 to 10 carbon atoms;
For example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene,
1-octene, 1-decene, etc. are used. Further, as the polyene component, 1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinylnorbornene, etc. are preferably used. Furthermore, the ethylene content of these amorphous copolymers is preferably in the range of 50 to 87 mol%, particularly 63 to 80 mol%. The amorphous copolymer used as the base polymer of the latex composition in the present invention has an intrinsic viscosity of 0.5 to 2.0 dl/in a decahydronaphthalene solution at 135°C, among the copolymers having the above-mentioned structure.
g, especially in the range 0.7 to 1.5 dl/g. That is, the average molecular weight of the amorphous copolymer used is
It has an important effect on particle size control during latex formation and on the properties of the resulting latex composition. For example, when the above-mentioned intrinsic viscosity is smaller than 0.5 dl/g, when a thermoplastic graft copolymer resin is produced using the resulting crosslinked latex composition as a starting material, the resin may be unsatisfactory in terms of impact resistance, etc. Become something. Furthermore, if a material with an intrinsic viscosity exceeding 2.0 dl/g is used, it becomes difficult to control the average particle size of the solid content in the latex to 0.3 μm or less, and the storage stability of the composition itself decreases. Crosslinked latex composition The composition of the present invention comprises the above-mentioned amorphous copolymer component as a base polymer, and at least one modified product of a crystalline low molecular weight α-olefin copolymer with an unsaturated carboxylic acid compound. Crosslinked latex compositions have several properties not found in conventional latex compositions. First, the composition of the present invention has an average particle size of solid content of
It is in the range of 0.2 to 3 μm, preferably 0.3 to 2.0 μm. Here, the average particle size is defined as the point where a weight histogram by particle size and a cumulative weight histogram are created using a predetermined particle size measuring device, and the cumulative weight histogram becomes 50%. If this average particle size is smaller than 0.2μm,
The thermoplastic graft copolymer obtained using this cross-linked latex composition as a base material will be insufficient in impact resistance and gloss. On the other hand, if it exceeds 3 μm, the latex state during graft polymerization will become unstable and its The resulting graft copolymers are highly unsatisfactory in terms of weather resistance, impact resistance and gloss. In addition, the crosslinked latex composition of the present invention has a hot toluene insoluble amount (gel fraction) of the amorphous copolymer component.
is in the range 30 to 95% by weight, preferably 60 to 90% by weight. This gel fraction is a measure of the degree of crosslinking, and is usually measured as the insoluble fraction in toluene at 120°C. Detailed measurement methods will be explained in Examples below. When the gel fraction is lower than 30% by weight, the resulting thermoplastic graft copolymer has unsatisfactory impact resistance and gloss, while when the gel fraction exceeds 95% by weight, the impact resistance decreases. invite Furthermore, the crosslinked latex composition of the present invention has a density of 0.90.
It contains a modified copolymer obtained by graft-modifying a crystalline low molecular weight α-olefin copolymer of g/cm ³ or more with an unsaturated carboxylic acid compound alone or in combination of two or more. This modified copolymer can easily refine amorphous copolymer particles such as rubber during latex formation, improving storage stability, and also improves the gloss of the thermoplastic graft copolymer obtained from the crosslinked latex composition. It has the ability to significantly improve The α-olefin copolymer used in this modified copolymer can be either wax-like or liquid at room temperature.
It is also possible to use both together. (1) The waxy copolymer is generally an ethylene-propylene copolymer and/or an ethylene-1 copolymer.
-butene copolymers are used. Copolymers useful for the purposes of this invention have a density
It has a softening point of 0.90 g/cm ³ or more and a softening point of 90°C or more, preferably 95°C or more. (2) A useful liquid copolymer is one having an intrinsic viscosity of 0.01 to 0.3 dl/g in the state of a decahydro-naphthalene solution at 135°C. These wax-like or liquid copolymers are used as modified products containing the below-described unsaturated carboxylic acid compound as a graft copolymerization component. As the modified copolymer, a modified polyethylene wax graft-modified with an unsaturated carboxylic acid compound and a modified ethylene/α-olefin copolymer are used. The unsaturated carboxylic acid compound used as a modifier is one or more selected from the group consisting of unsaturated carboxylic acids containing 3 to 10 carbon atoms, their acid anhydrides, their amides, their imides, and their esters. For example, acrylic acid, (meth)
Acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, norbornenedicarboxylic acid,
Tetrahydrophthalic acid, bicyclo[2,2,1]
Unsaturated carboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-
Unsaturated carboxylic acid anhydrides such as 5,6-dicarboxylic anhydride, amides or imides such as maleic acid monoamide, maleic acid diamide, maleimide, methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, maleic acid diethyl acid, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate, dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate,
Examples include unsaturated carboxylic acid esters such as glycidyl (meth)acrylate. Among these, preferred are maleic anhydride, maleic monoamide, maleic diamide, maleimide,
These include monomethyl maleate, diethyl maleate, glycidyl (meth)acrylate, and the like. Such a graft copolymer component usually accounts for 0.2 to 50%, preferably 0.2 to 50%, based on the weight of the modified copolymer.
Denaturation may be carried out so that the content is 0.2 to 20%.
At a content of 20% or less, there is almost no change in the softening point of the modified copolymer. In addition, as a modified copolymer, modified ethylene and α-
When using an olefin random copolymer,
The intrinsic viscosity of decahydronaphthalene solution at 135℃ is
0.01 to 0.3 dl/g of modified copolymer is preferred. Such a modified low molecular weight α-olefin copolymer contains 2 parts by weight per 100 parts by weight of the above-mentioned amorphous copolymer component.
It is necessary that it be contained in the latex composition in the range of 50 to 50 parts by weight, particularly 5 to 40 parts by weight. If used in an amount smaller than this range, it will tend to be difficult to refine the polymer when forming a latex, and if a large amount is used, the thermoplastic properties obtained from the crosslinked latex composition will be reduced. The copolymer becomes unsatisfactory in terms of impact resistance and strength. Production of crosslinked latex composition The crosslinked latex composition of the present invention has an intrinsic viscosity of 0.5 in a decahydronaphthalene solution at 135°C.
The crystalline low molecular weight α-
It is obtained by uniformly dispersing an olefin copolymer modified with an unsaturated carboxylic acid compound in an aqueous medium and crosslinking it in a latex state. When the intrinsic viscosity of the amorphous copolymer used is outside the above range, as detailed in the section on the amorphous copolymer, particle size adjustment during latex formation and properties of the resulting crosslinked latex composition may need to be adjusted. This will cause inconvenience in terms of aspects. Uniform dispersion of a polymer in an aqueous medium can be achieved, for example, by dissolving the polymer in a solvent such as n-hexane, and then stirring the solution into an aqueous medium in which an appropriate amount of a surfactant has been dispersed. The mixture may be mixed and dispersed, then heated to an appropriate temperature, and the solvent component may be removed by distillation. Also, if no solvent is used. A latex may be formed by kneading an amorphous copolymer or the like and an aqueous medium containing a surfactant using an extruder or the like. As the surfactant, any surfactant such as anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used, and anionic surfactants such as fatty acid sodium and fatty acid potassium can be preferably used. The amount of surfactant to be used varies depending on the type of polymer component used, etc., but is generally preferably selected at a ratio of 0.2 to 20 parts by weight per 100 parts by weight of the amorphous copolymer. Note that the amount of the aqueous medium to be used is preferably selected from the viewpoint of handling properties based on the product latex so that the solid content concentration in the latex is in the range of 5 to 65% by weight. The crosslinking treatment of the latex can be carried out by mixing a polyfunctional monomer into the latex and using a method known per se such as ionizing radiation crosslinking or organic peroxide crosslinking. As the polyfunctional monomer to be used, for example, monomers having two or more ethylenically unsaturated bonds, especially vinyl bonds, etc. are preferably used, and specific examples include divinylbenzene, tetramethylene diacrylate, glyceryl triacrylate, and ethylene glycol diacrylate. Examples include methacrylate, 1,2,4-trivinylcyclohexane, and tetraallyloxyethane. This polyfunctional monomer is an amorphous copolymer with 100%
It is desirable to use it in a range of 0.1 to 20 parts by weight, particularly 0.3 to 5 parts by weight. For crosslinking with ionizing radiation, any of α rays, β rays, γ rays, electron beams, X rays, etc. may be used. The irradiation dose is 1 Mrad
A range of 50 Mrad to 50 Mrad is desirable. Organic peroxide crosslinking is carried out by uniformly dispersing the organic peroxide in the latex and then heating the latex above the decomposition temperature of the organic peroxide. The organic peroxide used is preferably one with a 10-hour half-life temperature of 0°C or higher and 100°C or lower in view of the stability of the latex particles, the stability of the crosslinking reaction operation, and economic efficiency.Specifically, the following organic peroxides are preferred. Can give examples of things. 1,1-bis(t-butylperoxy)cyclohexane, t-butylperoxybiparate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2 , 5-di(benzoylpoxy)hexane, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, isobutyl peroxide, diisopropyl peroxide Dicarbonate, di(2-ethylhexyl) peroxycarbonate. The amount of organic peroxide added is usually 0.1 per 100 parts by weight of the amorphous copolymer component in the latex.
Suitable amounts are from 1 to 20 parts by weight, preferably from 1 to 10 parts by weight. The crosslinking conditions such as heating time for crosslinking may be normal pressure or pressurized, but the content of hot toluene insoluble matter in the amorphous copolymer component is 30% by weight or more, preferably 50% by weight or more, Most preferably, it is set to 60% by weight or more. Specifically, it is appropriate to set the heating time to 5 to 7 times the normal half-life. Thus, in the latex composition of the present invention, crosslinks are formed in the amorphous copolymer that is the base polymer, thereby improving the so-called grafting efficiency, and using the composition as a starting material, impact resistance, weather resistance and It becomes possible to obtain a thermoplastic graft copolymer resin that is excellent in various properties such as surface gloss. In addition, the crosslinked latex composition of the present invention may contain known compounding agents such as pigments, thickeners, plasticizers, preservatives, antifoaming agents, and PH regulators in known amounts, depending on the intended use. can do. Of course, these compounding agents may be blended into the latex before crosslinking, or
It may also be blended after crosslinking. Application of the Invention The crosslinked latex composition of the present invention can be graft-copolymerized with an alkenyl aromatic compound and a monomer copolymerizable with the compound, thereby improving impact resistance and weather resistance. A thermoplastic graft copolymer with remarkable properties such as surface gloss and surface gloss can be obtained. Examples of alkenyl aromatic compounds include styrene,
α-methylstyrene, p-methylstyrene, o-
Methylstyrene and the like may be used alone or in combination of two or more. Monomers that can be copolymerized with alkenyl aromatic compounds include, for example, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and octyl acrylate, and methacrylate. Methyl acid, ethyl methacrylate,
Methacrylic acid esters such as butyl methacrylate and octyl methacrylate are used alone or in combination of two or more. The amount of these used varies depending on the type, but in general, for alkenyl compounds, it is usually 40 to 500 parts by weight per 100 parts by weight of the rubber component in the crosslinked latex, and the amount of monomers that can be copolymerized with the alkenyl compound is Generally, crosslinking is carried out in an amount of 20 to 300 parts by weight per 100 parts by weight of the rubber component in the processed latex. Graft copolymerization of the crosslinked latex composition with an alkenyl compound and a monomer copolymerizable with the compound is carried out by a method known per se, for example, by adding the alkenyl aromatic compound etc. to the crosslinked latex, and then This is done by adding a predetermined amount of a radical generator and heating it, or by irradiating it with radiation. The thermoplastic graft copolymer obtained in this manner is significantly superior in properties such as impact resistance, weather resistance, and surface gloss, as shown in the examples below. The invention is illustrated by the following example. Example 1 Ethylene, propylene, and amorphous copolymers
Ethylidene norbornene copolymer rubber (ethylene unit content 72 mol%, contains 5-ethylidene norbornene units as a polyene component with an iodine value of 15,
The intrinsic viscosity [η] in decalin at 135℃ is 0.8dl.
0.8dl/g, hereinafter abbreviated as EPT) to 100g of modified polyethylene wax (density 0.93g/ ^cm3 , softening point 111℃,
15 g of maleic anhydride (containing 3% by weight) was dissolved in 900 g of n-hexane and stirred until uniform. Next, after dispersing 5 g of potassium olefinate as a surfactant in 900 g of water, using a homomixer (stirring blade rotation speed 12000 rpm),
Mixed with the above solution for 30 minutes. N-hexane was distilled off from the resulting emulsion at a temperature of 60°C to 80°C to obtain a latex. The average particle size of this composition is 0.5 μm, and the gel fraction is 71% by weight.
It was hot. The method for measuring the average particle diameter and gel fraction is as follows. (1) Measurement of average particle size Using a Coulter Counter manufactured by Coulter Electronics, all particles of the latex composition are counted, and a weight histogram by particle size and a cumulative weight histogram are created. Here, the point where the cumulative weight histogram becomes 50% is defined as the average particle diameter. (2) Amount insoluble in hot toluene (gel fraction) The total solid content in the latex composition was coagulated and dried, and 1.5g was collected in a 100-mesh stainless steel mesh bag, and dissolved in 100c.c. of toluene at 120℃. Soak for 6 hours. Next, it was taken out and dried, and then the weight of the residue in the mesh bag was measured, and the amount of hot toluene insoluble (gel fraction) was calculated, which was used as a measure of the degree of crosslinking. Next, using the obtained crosslinked latex composition as a base material, the following formulation was applied at 70°C under an _N2 atmosphere.
A graft polymerization reaction was carried out for 4 hours, and the latex was coagulated with magnesium sulfate, washed with water, dehydrated, and dried to obtain a thermoplastic polymer for testing. Prescription crosslinked latex composition (as EPT)
20 Parts by weight Styrene 57 Acrylic nitrile 23 N-dodecyl mercaptan 0.3 Sodium laurate 2.5 Cumene hydroperoxide 0.7 Dextrose 1.0 Sodium pyrophosphate 0.5 Ferrous sulfate 0.01 Water 180 This thermoplastic injection of polymer It was molded and various properties such as impact resistance, weather resistance, and surface gloss were determined. The results are shown in Table 1. The measurement method is as follows. (3) Impact resistance (Izotsu impact strength, Kg・cm/
cm) Conforms to ASTM D256-56. (4) Weather resistance (%) With ultraviolet carbon arc weather meter,
It is expressed as the retention of Izot impact strength after 500 hours of exposure under ASTM D1435 conditions. (5) Surface gloss (%) According to ASTM D523. Comparative example 1 Intrinsic viscosity [η] in decalin at 135°C is 2.2
A crosslinked latex composition and a thermoplastic polymer were prepared in exactly the same manner as in Example 1, except that EPT of dl/g was used and no modified polyethylene wax was blended. Their properties are shown in Table 1. Examples 2 to 4 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 1 except that the amount of modified polyethylene wax was 12 g and the intrinsic viscosity of EPT was changed. Their various properties are shown in Table 1. Comparative Example 2 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 1, except that the amount of modified polyethylene wax was 25 g and the intrinsic viscosity of EPT was 0.4 dl/g. Their various properties are shown in Table 1. Comparative Example 3 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 1, except that the modified polyethylene wax was not blended and the stirring and mixing time using a homomixer during latex formation was 60 minutes. A combination was prepared. Their various properties are shown in Table 1. Comparative Example 4 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 1 except that the amount of modified polyethylene wax was 12 g and the intrinsic viscosity of EPT was 2.2 dl/g. Their various properties are shown in Table 1.

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[Table] Examples 5 to 8 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 3, except that the amount of modified polyethylene wax was 14 g and the irradiation dose during crosslinking was varied. Their various properties are shown in Table 2. Comparative Examples 5 and 6 A crosslinked latex composition and a thermoplastic polymer were prepared in the same manner as in Example 2, except that the irradiation dose during crosslinking was varied. Their various properties are shown in Table 2.

[Table] Examples 9 to 11 A crosslinked rubber latex composition and a thermoplastic polymer were prepared in the same manner as in Example 1, except that the maleic anhydride content of the modified polyethylene wax, its blending amount, and the intrinsic viscosity of EPT were varied. did. Table 3 shows these various properties. Examples 12 to 15 A modified ethylene-propylene copolymer with an ethylene content of 72 mol% and an intrinsic viscosity of 0.2 dl/g in decalin at 135°C was used instead of the modified polyethylene wax, and its maleic anhydride content A crosslinked rubber latex and a thermoplastic polymer were prepared in the same manner as in Example 1, except that the compounding amount and the intrinsic viscosity of EPT were varied. Table 4 shows these various properties.

【table】

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Claims (1)

[Claims] 1 An ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer having an intrinsic viscosity in a decahydronaphthalene solution at 135°C in the range of 0.5 to 2.0 dl/g and the non-amorphous copolymer. Consisting of an unsaturated carboxylic acid compound modified product of a crystalline low molecular weight α-olefin copolymer with a density of 0.90 g/cm ³ or more in an amount of 2 to 50 parts by weight per 100 parts by weight of the crystalline copolymer, and is polyfunctional. A crosslinked latex composition in which crosslinking bonds are formed using a monomer as a crosslinking aid, and the average particle size of the solid content is 0.2 to 0.2.
A crosslinked latex composition for a thermoplastic graft copolymer resin, characterized in that the amorphous copolymer component has a diameter of 3.0 μm and a hot toluene insoluble content of the amorphous copolymer component of 30 to 95% by weight.