JPH0582415B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a latex composition containing an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin polyene amorphous copolymer as a main component, and a method for producing the same. The present invention relates to a crosslinked amorphous copolymer latex composition in which crosslinked bonds are formed in the molecular chains of the amorphous copolymer, and a method for producing the same. PRIOR ART AND TECHNICAL PROBLEMS TO BE SOLVED A method of crosslinking an aqueous dispersion of a polymer with ionizing radiation is known from JP-A-52-121054, and a radiation-vulcanized rubber latex composition is
This is known from Japanese Patent Application Laid-Open No. 153034/1983. However, an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer that is nonpolar and has no unsaturated bonds in its main chain may form fine particles in a latex state. However, since it is difficult to obtain a crosslinked rubber latex composition and its storage stability is poor, a practically usable crosslinked rubber latex composition containing these amorphous donor polymers as a main component has not yet been known. The crosslinked rubber latex containing the above-mentioned ethylene/α-olefin amorphous copolymer as its main component has excellent weather resistance and electrical insulation properties, and is therefore suitable for use in industrial rubber gloves and electrical gloves. It is attracting attention in the fields of rubber products and resin modifiers, such as dip-molded products such as typified by , and cast-molded products such as footwear soles. In this case, in rubber product applications, excellent film forming properties and high strength after film formation are required, and in the field of resin modifiers, excellent impact strength and weather resistance improving effects are required. From this point of view, it is necessary for the crosslinked rubber latex composition that the average particle size of the solid content is in the range of 0.2 to 3.0 μm, and that the content of hot toluene insoluble matter in the rubber component is 30% by weight or more. Object of the Invention Therefore, the object of the present invention is to provide a crosslinked amorphous copolymer latex composition containing an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin amorphous copolymer as a main component; We would like to share with you the manufacturing method. Another object of the present invention is to provide a crosslinked latex composition containing the above-mentioned crystalline copolymer as a main component, which has excellent storage stability, and a method for producing the same. Still another object of the present invention is to provide a crosslinked latex composition that is particularly useful in the fields of rubber product applications and resin modifiers. Structure of the Invention According to the present invention, (A) a rubbery polymer component consisting of an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer; 2 to 100 parts by weight of crystalline copolymer (A)
50 parts by weight of low molecular weight polyethylene, low molecular weight ethylene/α-olefin copolymer, unsaturated carboxylic acid compound graft modified low molecular weight polyethylene, unsaturated carboxylic acid compound graft modified low molecular weight ethylene/α-olefin copolymer. A crosslinked amorphous latex composition containing at least one component selected from the above as a polymer component, characterized in that the amorphous polymer component has a crosslinked bond formed therein. A quality copolymer latex composition is provided. According to the present invention, (A) an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin (B) 2 to 100 parts by weight of the amorphous copolymer (A) to the polyene amorphous copolymer;
50 parts by weight of low molecular weight polyethylene, low molecular weight ethylene/α-olefin copolymer, unsaturated carboxylic acid compound graft modified low molecular weight polyethylene, unsaturated carboxylic acid compound graft modified low molecular weight ethylene/α-olefin copolymer. At least one selected from these is blended and uniformly dispersed in an aqueous medium in the presence of a surfactant to form an amorphous copolymer latex, and then crosslinked in the latex state. A method for producing a crosslinked amorphous copolymer latex composition 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. The α-olefin constituting such an amorphous polymer includes α-olefins having 3 to 10 carbon atoms, such as 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
It 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, if the above-mentioned intrinsic viscosity is smaller than 0.5 dl/g, the strength of the resulting film will be significantly reduced when the resulting crosslinked latex composition is formed into a film. Also, if the intrinsic viscosity exceeds 2.0 dl/g, the average particle size of the solid content in the latex will be 3.0 μm.
m, and as a result, there arises the disadvantage that not only the storage stability decreases, but also the film strength when formed. This amorphous copolymer is typified by so-called rubber, but as a result of X-ray diffraction measurements, the crystallinity is
Copolymers with low crystallinity of less than 15% may also be used. Low molecular weight olefin or olefin copolymer and modified low molecular weight olefin or olefin copolymer Low molecular weight polyolefin or olefin copolymer, modified low molecular weight polyolefin or The olefin copolymer easily makes the aforementioned amorphous copolymer (hereinafter simply referred to as rubber) fine when it is made into a latex, and when this composition is used as a resin modifier, it is It functions to significantly improve the gloss of the plastic graft copolymer. As this low molecular weight polyolefin or olefin copolymer (hereinafter sometimes simply referred to as olefin copolymer), both wax-like and liquid forms at room temperature can be used.
It is also possible to use both together. Examples of low molecular weight polyolefins include wax-like or liquid polyethylene. Among low-molecular weight olefin copolymers, wax-like copolymers are generally ethylene-propylene copolymers, ethylene-1-butene copolymers, etc. - Examples include α-olefin copolymers. Copolymers useful for the purposes of this invention have a density
0.90g/ ^cm3 or more, softening point (vikatsuto) 90℃ or more,
Preferably the temperature is 95°C or higher. Useful liquid copolymers have an intrinsic viscosity of 0.01 to 0.3 dl/g in a decahydronaphthalene solution at 135°C. These wax-like or liquid polymers or copolymers can also be used as modified products containing the below-described unsaturated carboxylic acid compound as a graft copolymerization component. In addition, modified polymers or copolymers include modified polyethylene wax graft-modified with unsaturated carboxylic acid compounds and modified ethylene α-
Olefin copolymers 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- Unsaturated carboxylic acid anhydrides such as ene-5,6-dicarboxylic anhydride, amides or imides such as maleic acid monoamide, maleic acid diamide, maleimide, methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate , diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate, bicyclo[2,2,
1] Unsaturated carboxylic acid esters such as dimethyl hept-2-ene-5,6-dicarboxylate and glycidyl (meth)acrylate. Among these, preferred are maleic anhydride, maleic monoamide, maleic diamide, maleimide, monomethyl maleate, diethyl maleate, glycidyl (meth)acrylate, and the like. Such graft copolymerization component is usually 0.2 to 50%, preferably 0.2 to 50%, based on the weight of the modified copolymer.
Denaturation should be carried out so that the content is 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 low molecular weight olefin polymers or copolymers or modified olefin polymers or copolymers can be used alone or in combination, and in either case, the above-mentioned amorphous copolymer component can be used.
2 to 50 parts by weight, especially 5 to 40 parts by weight per 100 parts by weight
It is necessary that it be contained in the latex composition in a range of parts by weight. If used in an amount less than this range, it will be difficult to make the polymer finer when forming a latex from these polymer components, resulting in disadvantages such as a decrease in storage stability. In such cases, problems such as a decrease in film strength occur when the composition is formed into a film. Production of a crosslinked latex composition According to the invention, the aforementioned amorphous copolymer having an intrinsic viscosity in a decahydronaphthalene solution at 135° C. ranges from 0.5 to 2.0 dl/g, in particular from 0.7 to 1.5 dl/g. At least one type of low molecular weight polymer among the above-mentioned low molecular weight polyolefin or polyolefin copolymer or modified low molecular weight polyolefin or polyolefin copolymer is uniformly dispersed in an aqueous medium in the above-mentioned amount in the presence of a surfactant. Allow to form latex. When the intrinsic viscosity of the amorphous copolymer used is outside the above range, as detailed in the section on amorphous copolymers, particle size adjustment during latex formation and properties of the resulting crosslinked latex composition may be affected. This will cause inconvenience in terms of aspects. 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. In forming the latex, for example, an amorphous copolymer and a low molecular weight α-olefin copolymer are uniformly dissolved in a hydrocarbon solvent such as n-hexane, and then a predetermined amount of the interfacial The above solution may be mixed and dispersed with stirring in an aqueous medium in which the activator is dispersed, and then heated to an appropriate temperature to distill off the solvent component. The amount of aqueous medium such as water to be used is preferably selected so that the solid content concentration in the latex is usually in the range of 5 to 65% by weight based on the product latex, from the viewpoint of handling properties in the latex state. According to the present invention, this latex is then subjected to a crosslinking treatment to form crosslinked bonds in the molecular chains of the amorphous polymer, thereby obtaining a crosslinked latex composition. Such a crosslinking treatment of the latex can be carried out by distributing a polyfunctional monomer in 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 preferable 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 preferably in the range of 1 Mrad to 50 Mrad. 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 to be used is preferably one with a 10-hour half-life temperature of 0°C or more and 100°C or less from the viewpoint of stability of latex particles, safety of cross-linking reaction operation, and economical efficiency.Specifically, the following organic peroxides are preferred. I can give an example. 1,1-bis(t-butylperoxy)cyclohexane, t-butylperoxybiparate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2 , 5-di(benzoylperoxy)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 generally 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the amorphous copolymer component in the latex. The crosslinking conditions such as heating time for crosslinking may be normal pressure or pressurized, but the hot toluene insoluble content of the amorphous polymer component is 30% by weight or more, preferably 50% by weight or more.
It is set to be at least 60% by weight, most preferably at least 60% by weight. Specifically, it is appropriate to set the heating time to 5 to 7 times the normal half-life. The above hot toluene insoluble content (gel fraction)
is expressed as the proportion of the total solid content in the latex that is insoluble in toluene at 120°C, and is a measure of the degree of crosslinking. Detailed measurement methods will be described in Examples below. When this gel fraction is smaller than the above-mentioned range, the film strength after film formation, impact resistance improvement effect, weather resistance improvement effect, etc. will be insufficient. Crosslinked latex composition The thus obtained ethylene/α-olefin amorphous copolymer or ethylene/α-olefin
A crosslinked latex composition containing a polyene amorphous copolymer as a main component has an average particle size of 0.2 to 0.2
A composition with a particle size in the range of 3.0 μm, excellent storage stability, etc., and a gel fraction of 30% by weight or more, which is extremely excellent in film strength after film formation, impact resistance improvement effect, weather resistance improvement effect, etc. It is. In addition, the crosslinked latex composition may contain pigments, thickeners, plasticizers, preservatives, antifoaming agents, etc. depending on its use.
Known compounding agents such as PH adjusters can be compounded in amounts known per se. Of course, these compounding agents may be blended into the latex before crosslinking, or may be blended after crosslinking. Such crosslinked latex compositions are particularly useful in the fields of rubber products and resin modification. The invention is illustrated by the following example. Example 1 Ethylene-propylene-ethylidenenorbornene copolymer rubber
100g Ethylene unit content: 72 mol%, Contains 5-ethylidene norbornene units as a polyene component with an iodine value of 15, [η] in decalin at 135℃ is 0.8 dl/g Modified polyethylene wax 10g Steamed maleic acid unit content: 3 weight % Density 0.93g/cc Softening Point 111°C was dissolved in 900g of n-hexane and stirred until homogeneous. Then potassium oleate 5 was used as a surfactant.
g in 900 g of water, and then mixed with the above solution for 30 g using a homomixer (stirring blade rotation speed 1200 rpm).
mixed for minutes. While gently stirring the resulting emulsion, n-hexane was distilled off at a temperature of 60 to 80°C to obtain a latex. The rubber content is added to the latex obtained in this way.
2 parts by weight of p-divinylbenzene was added to 100 parts by weight and thoroughly dispersed. Next, the latex was transferred to an electron beam irradiation container to a thickness of 1.5 mm, the top of the container was sealed with a 30 μm polyethylene coil film, and the accelerating voltage was 750 KV.
A crosslinked latex composition was prepared by irradiating with an electron beam at 10 Mrad. The following measurements were performed on this composition sample,
The results are shown in Table 1. (1) Rubber coagulation and precipitate sample composition made of 100 mesh stainless steel
The amount of rubber solidified and precipitated remaining on the latex is expressed as weight % based on the total solid content in the latex. (2) Measurement of average particle size Using a Coulter Counter manufactured by Coulter Electronics, all particles in the latex composition are counted, and a weight histogram by particle size and a cumulative amount histogram are created. Here, the point where the cumulative weight histogram becomes 50% is defined as the average particle diameter. (3) 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. For measurements (1) to (3) above, after electron beam irradiation
Measurements were completed within 48 hours. (4) Measurement of film strength The latex composition after electron beam irradiation was coated on a glass plate within 48 hours and left at room temperature for 44 hours to obtain a dry film with a thickness of 200 μm. This film is subjected to a tensile test in accordance with JIS K 6301 to determine the film strength. (5) Evaluation of storage stability A latex composition sample was placed in a sealed container and left at room temperature for 2 months. Next, the amount of rubber coagulation and precipitation was measured in the same manner as in (1), which was used as a measure of the storage stability of the crosslinked rubber latex. Examples 2 and 3 and Comparative Examples 1 and 2 Crosslinked rubber latex was produced in the same manner as in Example 1 except that the intrinsic viscosity of the ethylene-propylene-ethylidene norbornene copolymer rubber was changed, and various properties were measured. The measurement results are also shown in Table 1. Example 4 A crosslinked rubber latex was produced in the same manner as in Example 1 except that 20 g of modified polyethylene wax was used, and various properties were measured. The results are shown in Table 1.

【table】

[Table] Examples 5 and 6 and Comparative Examples 3 and 4 Same as Example 1 except that the maleic anhydride content of the modified polyethylene wax was changed and ethylene propylene ethylidene norbornene rubber with an intrinsic viscosity of 1.5 dl/g was used. A crosslinked latex was produced in the same manner and its properties were measured. The measurement results are shown in Table 2. Examples 7 to 9 and Comparative Example 5 Crosslinked latex was produced in the same manner as in Example 5, except that the amount of modified polyethylene wax was changed, and its properties were measured. The measurement results are shown in Table 3.

【table】

【table】

[Table] Examples 10 and 11 A crosslinked latex composition was produced in the same manner as in Example 5 except that the amount of divinylbenzene was changed, and its properties were measured. The results are shown in Table 4. Examples 12 and 13 and Comparative Examples 6 and 7 Crosslinked latex compositions were produced in the same manner as in Example 5, except that the electron beam irradiation dose was changed, and their properties were measured. The results are shown in Table 4.

[Table] Examples 14 to 16 The following modified low molecular weight α-olefin polymers are used. Modified ethylene/propylene copolymer Maleic anhydride content 3% by weight Ethylene content 72 mol% Intrinsic viscosity (135℃, Decalin solution) 0.2dl/g Density 0.85g/cm ^3Kinematic viscosity (100℃) 2300C.S. A crosslinked latex composition was prepared in the same manner as in Example 12, except that the copolymer was used in place of the modified polyethylene wax and the amount of the copolymer was varied. Various properties are shown in Table 5. Example 17 A crosslinked latex composition was prepared in the same manner as in Example 14, except that a modified ethylene/α-olefin copolymer containing 10% by weight of maleic anhydride was used.
Various properties were measured. The results are shown in Table 5.

[Table] Examples 18 to 20, Comparative Example 8 As a low molecular weight α-olefin copolymer, unmodified polyethylene wax (density 0.92 g/cm ³ ,
A cross-linked latex composition was prepared in the same manner as in Example 14, except that a compound with a softening point of 113° C. was used and the blending amount was varied, and various properties were measured. The results are shown in Table 6.

【table】

[Table] Example 21 A latex is prepared in the same manner as in Example 12.
In this latex, p is added to 100 parts by weight of rubber.
- 2 parts by weight of divinylbenzene was added and thoroughly dispersed. Next, this latex was transferred to the autoclave No. 2, and 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane (trade name Perhexa 3M, manufactured by NOF Corporation) was added as an organic peroxide.
After adding 3.0 g, a crosslinking reaction was carried out at a temperature of 120° C. for 2 hours while stirring to produce a crosslinked latex composition. Various properties of this composition were measured in the same manner as in Example 1, and the results are shown in Table 7. Example 22 A cross-linked latex was prepared in the same manner as in Example 21, except that 6 g of benzoyl peroxide (Nyper BO ^* 50% product, manufactured by NOF Corporation) was used as the organic peroxide and the cross-linking reaction was carried out at a temperature of 100°C. A composition was prepared and various properties were measured. The results are shown in Table 7.

[Table] **Using benzoyl peroxide

Claims (1)

[Scope of Claims] 1 (A) a rubbery polymer component consisting of an ethylene/α-olefin amorphous copolymer or an ethylene/α-olefin/polyene amorphous copolymer; (B) the amorphous 2 to 100 parts by weight of copolymer (A)
50 parts by weight of low molecular weight polyethylene, low molecular weight ethylene/α-olefin copolymer, unsaturated carboxylic acid compound graft modified low molecular weight polyethylene, unsaturated carboxylic acid compound graft modified low molecular weight ethylene/α-olefin copolymer. A latex composition containing at least one component selected from the above as a polymer component, characterized in that the amorphous rubbery polymer component has a crosslink bond formed therein. Amorphous copolymer latex composition. 2. Claim 1, wherein the amorphous polymer component has a hot toluene insoluble content of 30% by weight or more.
The latex composition described in . 3. The latex composition according to claim 1, wherein the solid content has an average particle size of 0.2 to 3.0 μm. 4 (A) Ethylene/α-olefin amorphous copolymer or ethylene/α-olefin/polyene amorphous copolymer having an intrinsic viscosity in the range of 0.5 to 2.0 dl/g in a decahydronaphthalene solution at 135°C. (B) 2 to 100 parts by weight of the amorphous copolymer (A);
50 parts by weight of low molecular weight polyethylene, low molecular weight ethylene/α-olefin copolymer, unsaturated carboxylic acid compound graft modified low molecular weight polyethylene, unsaturated carboxylic acid compound graft modified low molecular weight ethylene/α-olefin copolymer. At least one selected from these is blended and uniformly dispersed in an aqueous medium in the presence of a surfactant to form an amorphous copolymer latex, and then crosslinked in the latex state. A method for producing a crosslinked amorphous copolymer latex composition.