JPH0794577B2 - Latex composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an amorphous polymer of an ethylene / α-olefin-based amorphous copolymer and an aliphatic conjugated diene (hereinafter referred to as “polyconjugated diene”). May be abbreviated) and a latex composition containing as a main component, more specifically, weather resistance,
The present invention relates to a latex composition suitable for producing a thermoplastic resin having excellent impact resistance and surface gloss.

(Prior Art) Weather resistance by graft-polymerizing an alkenyl aromatic compound and a vinyl monomer copolymerizable therewith to an ethylene / α-olefin copolymer rubber or an ethylene / α-olefin / polyene copolymer rubber Some attempts have been made to obtain a thermoplastic resin excellent in impact resistance, surface gloss and the like.

For example, JP-B-43-16394 discloses a method of obtaining a thermoplastic resin by making the rubber component into a latex state and gelling it in the presence of a crosslinkable monomer such as divinylbenzene, and then performing graft copolymerization. JP-B-48-35718 discloses that the rubber particles in the latex are swollen with a liquid aliphatic hydrocarbon or alicyclic hydrocarbon, and graft copolymerization is performed in this state. A method is disclosed.

However, in any of the known prior arts, no thermoplastic graft copolymer resin having practically applicable levels of weather resistance, impact resistance, surface gloss, etc. has been obtained by any of the methods.

(Object of the Invention) That is, an object of the present invention is to provide a latex composition which is particularly useful for producing a thermoplastic graft copolymer resin excellent in various properties such as weather resistance, impact resistance, and surface gloss. .

(Structure of the Invention) According to the present invention, an ethylene / α-olefin-based amorphous copolymer (A) and the following general formula: In the formula, R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom, and an amorphous polymer (B) of aliphatic conjugated diene having a number average molecular weight of 500 to 5000 represented by By standard, A: B = 99: 1 to 80:20, and the average particle size of solids is 0.2 to 3.0μ.
There is provided a latex composition characterized by being in the range of m.

(Function) Ethylene, which is a constituent of the latex composition of the present invention,
The α-olefin-based amorphous copolymer imparts impact resistance and weather resistance to a thermoplastic resin obtained by graft-polymerizing an alkenyl aromatic compound and a vinyl monomer to this latex composition. is there.

The other component, the amorphous polymer (B) of an aliphatic conjugated diene, is a latex when a thermoplastic resin is obtained by graft-polymerizing an alkenyl aromatic compound and a vinyl monomer into this latex composition. It has a function as a graft active point on the particle side, and greatly improves the impact resistance and gloss of the resulting thermoplastic resin.

(Preferred Embodiment of the Invention) Ethylene / α-olefin-based amorphous copolymer (A) In the present invention, the amorphous copolymer used as the base polymer in the latex is ethylene / α-olefin amorphous. Copolymer or ethylene / α-olefin /
Mention may be made of polyene amorphous copolymers.

In the present specification, the term "amorphous copolymer" means not only a completely amorphous polymer typified by so-called rubber but also a low crystal having a crystallinity of 15% or less measured by an X-ray diffraction method. Also included are polymers of varying degrees.

The α-olefin constituting the amorphous copolymer is an 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 and the like are used.

As the polyene component, 1,4-hexadiene, 5-
Ethylidene-2-norbornene, dicyclopentadiene, 5-vinylnorbornene and the like are preferably used.

Further, the ethylene content of these amorphous copolymers is 50 to
It is preferably in the range of 87 mol%, particularly 63 to 80 mol%.

The amorphous copolymer used as the base polymer of the latex composition in the present invention is, among the copolymers having the above-mentioned constitution, an intrinsic viscosity in a decahydronaphthalene solution at 135 ° C. of 0.5 to 2.0 dl / g, particularly Those in the range of 0.7 to 1.5 dl / g are preferably used.

That is, the average molecular weight of the amorphous copolymer to be used has an important influence on the particle size control during latex formation and the properties of the latex composition obtained. For example, when the above-mentioned intrinsic viscosity is less than 0.5 dl / g, it becomes difficult to suppress the average particle size of solids in the latex to 0.2 μm,
When a thermoplastic graft copolymer resin is produced using the obtained latex composition as a starting material, the resin tends to be unsatisfactory in impact resistance and the like.

Further, when the one having an intrinsic viscosity of more than 2.0 dl / g is used, it becomes difficult to control the average particle diameter of the solid content in the latex to 3.0 μm or less, and the storage stability of the composition itself tends to decrease. There is.

Amorphous polymer of aliphatic conjugated diene (B) In the present invention, the component (B) to be combined with the component (A) is represented by the following general formula: In the formula, R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and an aliphatic conjugated diene represented by: for example, an amorphous polymer such as butadiene or isoprene is used.

The polymer may be of 1,2 addition type, 1,4 addition type, or cis type or trans type, but the impact resistance of the thermoplastic resin obtained by using the latex composition as a base material is high. From the viewpoint of being particularly excellent, it is desirable to use those in which 50% or more of the total binding amount is cis-1,4 addition type.

In addition, these polybutadiene and the like may have a reactive functional group such as a carbonyl group, a maleic acid group, and a hydroxyl group introduced into the main chain and the terminal of the molecule.

It is also important that the polymer component (B) described above in the present invention has a number average molecular weight in the range of 500 to 5,000.

As will be apparent from the examples described below, when the number average molecular weight is out of this range, the thermoplastic resin obtained using the latex composition as a base material becomes unsatisfactory in impact resistance and gloss.

Production of Latex Composition The latex composition of the present invention comprises the above-mentioned components (A) and (B) on a weight basis, A: B = 99: 1 to 80:20, particularly 95: 5 to 85:15. It is obtained by uniformly dispersing in an aqueous medium so that

When the weight of the amorphous copolymer of the component (A) exceeds the above range and is present in a large amount, during the production of the thermoplastic resin,
Since the graft ratio of the alkenyl aromatic compound or the like to the latex particles is reduced, the impact resistance of the thermoplastic resin becomes poor and the advantages of the present invention are lost.

Further, when the amorphous polymer of the component (B) such as polybutadiene is used in a larger amount than the above range, the thermoplastic resin obtained from the latex composition has poor weather resistance.

In the latex composition of the present invention, the component (A) and the component (B) are preferably mixed in the latex particles, and both are mixed by an extruder before being uniformly dispersed in the aqueous medium. It is desirable to keep it.

When uniformly dispersing an amorphous copolymer and polybutadiene in an aqueous medium, a crystalline low molecular weight α-olefin copolymer having a true density of 0.90 g / cm ³ or more or a modified copolymer thereof is used alone or in combination. It is preferable to use the above combination.

This crystalline copolymer and its modified copolymer are capable of easily refining particles of an amorphous copolymer such as rubber and particles of polybutadiene and the like at the time of forming a latex to improve storage stability. It has the function of remarkably improving the gloss of the thermoplastic graft copolymer obtained.

As the α-olefin copolymer, both a waxy one and a liquid one at room temperature can be used, and it is also possible to use both together.

(1) The waxy copolymer is generally ethylene-
A propylene copolymer and / or an ethylene-1-butene copolymer are used.

Copolymers useful for the purposes of the present invention have a density of 0.90 g / cm ³
As described above, the softening point (Vicat) is 90 ° C or higher, preferably 95 ° C or higher.

(2) A useful liquid copolymer is one having an intrinsic viscosity of 0.01 to 0.3 dl / g in a decahydro-naphthalene solution state at 135 ° C.

These waxy or liquid copolymers can also be used as modified products containing an unsaturated carboxylic acid compound described below 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 and their acid anhydrides, their amides, their imides and their esters. And, for example,
Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, norbornene dicarboxylic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid, etc. Unsaturated carboxylic acid anhydrides such as saturated carboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic anhydride Compounds, maleic acid monoamide, maleic acid diamide, amide or imide such as maleimide, methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconic acid, diethyl citraconic acid, Tetrahydrodimethyl phthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6- Carboxylic acid dimethyl, unsaturated carboxylic acid esters such as glycidyl (meth) acrylate, and the like. Among them, maleic anhydride, maleic acid monoamide, maleic acid diamide, maleimide, monomethyl maleate, diethyl maleate, glycidyl (meth) acrylate and the like are preferable.

The graft copolymer component may be modified so that it is usually contained in an amount of 0.2 to 50%, preferably 0.2 to 20% based on the weight of the modified copolymer. When the content is 20% or less, the softening point of the modified copolymer hardly changes.

When a modified ethylene / α-olefin random copolymer is used as the modified copolymer, a modified copolymer having a decahydronaphthalene solution at 135 ° C. with an intrinsic viscosity of 0.01 to 0.3 dl / g is preferable.

Such low molecular weight α-olefin copolymers or modified low molecular weight α-olefin copolymers can be used alone or in combination, and in any case, the total of the components (A) and (B) described above is used. 2 to 50 per 100 parts by weight
It is suitable to be contained in the latex composition in an amount of 5 parts by weight, particularly 5 to 40 parts by weight. If it is used in an amount less than this range, it tends to be difficult to make the polymer fine during the latex formation of these polymer components, and when blended in a large amount, the thermoplasticity obtained from the latex composition The copolymer becomes unsatisfactory in impact strength and the like.

Uniform dispersion of the amorphous copolymer (A), the conjugated diene polymer (B) and the crystalline low molecular weight α-olefin copolymer or the modified copolymer thereof, which is optionally added, in the aqueous medium is For example, after the polymer is dissolved in a solvent such as n-hexane, the solution is mixed and dispersed in an aqueous medium in which an appropriate amount of a surfactant is dispersed with stirring, and then heated to an appropriate temperature. The solvent component may be removed by distillation.

When the solvent is not used, the latex may be formed by kneading the amorphous copolymer and the aqueous medium containing the surfactant using an extruder or the like.

As the surfactant, any of an anion activator, a cation activator, a nonion activator and the like can be used, and an anion activator such as fatty acid sodium and fatty acid potassium can be preferably used. The amount of the surfactant used varies depending on the kind of the polymer component used and the like, but it is generally preferable to select 0.2 to 20 parts by weight per 100 parts by weight of the amorphous copolymer.

The amount of the aqueous medium used is preferably selected so that the solid content concentration in the latex is in the range of 5 to 65% by weight from the viewpoint of handling property based on the product latex.

Further, in the latex composition of the present invention, the latex particles so that the content of the hot toluene-insoluble matter in the amorphous copolymer (A) and the conjugated diene polymer (B) is in the range of 30 to 95% by weight. In order to improve the gloss of the thermoplastic resin obtained by using the latex composition as a base material, it is desirable to form crosslinks therein.

Such a crosslinking treatment of the latex can be performed by a known method such as ionizing radiation crosslinking or organic peroxide crosslinking, by adding a polyfunctional monomer into the latex as necessary.

As the polyfunctional monomer to be used, for example, a monomer having two or more ethylenic unsaturated bonds, particularly a vinyl bond is preferably used, and specifically, divinylbenzene, tetramethylene diacrylate, glyceryl triacrylate, ethylene glycol diethylene, etc. Examples thereof include methacrylate, 1,2,4-trivinylcyclohexane, tetraallyloxyethane and the like.

It is desirable to use the multi-potential monomer in an amount of 0.1 to 20 parts by weight, particularly 0.3 to 5 parts by weight, based on 100 parts by weight of the amorphous copolymer (A). Ionizing radiation crosslinking is a
Any of the rays, β rays, γ rays, electron rays, X rays and the like may be used. The irradiation dose is preferably in the range of 1 Mrad to 50 Mrad.

Crosslinking of the organic peroxide is carried out by uniformly dispersing the organic peroxide in the latex and then heating the latex at a temperature above the decomposition temperature of the organic peroxide.

As the organic peroxide used, stability of latex particles,
From the viewpoint of stability and economy of the crosslinking reaction operation, those having a 10-hour half-life temperature of 0 ° C. or higher and 100 ° C. or lower are preferable, and specific examples thereof include the following organic peroxides.

1.1-bis (t-butylperoxy) cyclohexane, t-butylperoxybiparate, t-bitylperoxy-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 peroxydicarbonate, Bis (2-ethylhexyl) peroxycarbonate.

The amount of the organic peroxide added is usually 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the amorphous copolymer component in the latex.

Crosslinking conditions such as heating time for crosslinking may be either normal pressure or pressure, but the content of the amorphous toluene component (A) and the conjugated diene copolymer component (B) insoluble in hot toluene Is 30% by weight or more, preferably 40% by weight or more, and most preferably 50% by weight or more. Specifically, it is appropriate that the heating time is usually 5 to 7 times the half-life.

Latex Composition The latex composition thus obtained contains ethylene / α-
An olefin-based amorphous copolymer (A) and an amorphous polymer of a conjugated diene such as polybutadiene (B) are the main components, and the average particle size of the solid content is in the range of 0.2 μm to 3.0 μm. .

In such a latex composition, the average particle size of the solid content is
When it is less than 0.2 μm, the impact resistance of the thermoplastic resin obtained by using the composition as a substrate becomes poor.

On the other hand, when it is larger than 3.0 μm, the stability of the latex is deteriorated when a thermoplastic resin is obtained by graft-polymerizing an alkenyl aromatic compound or the like to the composition, and as a result, the resin has high impact resistance. And the glossiness becomes unsatisfactory.

INDUSTRIAL APPLICABILITY The latex composition of the present invention has a high graft ratio of an alkenyl aromatic compound or the like to latex particles, and is extremely useful as a raw material for a thermoplastic resin having excellent properties such as impact resistance, weather resistance and surface gloss.

In addition, the latex composition of the present invention, known additives such as pigments, thickeners, plasticizers, preservatives, antifoaming agents, pH adjusters, etc. are added in a known amount per se according to the application. be able to. Of course, these compounding agents may be compounded in the latex before crosslinking or may be compounded after crosslinking.

Use of the Invention The latex composition of the present invention has impact resistance, weather resistance, surface gloss, etc., especially when it is graft-copolymerized with an alkenyl aromatic compound and a monomer copolymerizable with the alkenyl aromatic compound. A thermoplastic graft copolymer having remarkably excellent properties can be obtained.

As the alkenyl aromatic compound, styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene and the like are used alone or in combination of two or more.

Examples of the monomer copolymerizable with the alkenyl aromatic compound include vinyl cyan compounds such as acrylonitrile and methacrylonitrile, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate and octyl acrylate, and methacrylic acid. Methacrylic acid esters such as methyl acidate, ethyl methacrylate, butyl methacrylate and octyl methacrylate are used alone or in combination of two or more.

The amount of these used varies depending on the kind, but in general, in an alkenyl compound, generally 40 to 500 parts by weight relative to 100 parts by weight of the rubber component in the crosslinked latex, and a monomer copolymerizable with the alkenyl compound. In general, in 20 parts per 100 parts by weight of the rubber component in the crosslinked latex.
To 300 parts by weight.

Graft copolymerization of the latex composition with an alkenyl compound and a monomer copolymerizable with the alkenyl compound is carried out by a means known per se, for example, by adding the alkenyl aromatic compound or the like to a crosslinked latex and further adding a radical It is carried out by adding a predetermined amount of the generator and heating or irradiating with radiation.

The thermoplastic graft copolymer thus obtained is remarkably excellent in properties such as impact resistance and weather resistance surface gloss, as shown in Examples described later.

The invention is illustrated by the following example.

(Example) First, in the following examples, the methods for measuring the average particle diameter and gel fraction of the latex composition are as follows.

(1) Measurement of average particle size Using a Coulter counter manufactured by Coulter Electronics Co., Ltd., all particles of the latex composition were counted,
Create a weight histogram by particle size and a cumulative weight histogram. Here, the point where the cumulative weight histogram becomes 50% is defined as the average particle size.

(2) Amount of hot toluene insoluble (gel fraction) All solids in the latex composition are coagulated, dried, and collected in a 100 mesh stainless steel net bag (1.5 g) for 6 hours in 120 cc of toluene 100 cc. Soak. Then, this was taken out and dried, and the weight of the residue in the mesh bag was measured to calculate the amount of hot toluene insoluble (gel fraction), which was used as a measure of the degree of crosslinking.

The properties of various polybutadienes used as the amorphous polymer of the conjugated diene as the constituent (B) in the latex composition are shown in Table 1 below.

Also, using the latex composition as a base material, N
Graft polymerization reaction is carried out at 70 ° C. for 4 hours in ₂ atmospheres, latex is coagulated with magnesium sulfate, washed with water, dehydrated and dried to obtain a thermoplastic polymer for assay.

Prescription Crosslinked latex composition (as EPT) 20 parts by weight Styrene 57 〃 Acrylonitrile 23 〃 n-Dodecyl mercaptan 0.3 〃 Sodium laurate 2.5 ッ Cumene hydroperoxide 0.7 〃 Dextrose 1.0 〃 Sodium pyrophosphate 0.5 〃 Ferrous sulfate 0.01 〃 Water 180〃 This thermoplastic polymer was injection molded to determine various properties such as impact resistance, weather resistance and surface gloss. The measuring method is as follows.

(3) Impact resistance (Izod impact strength, Kg · cm / cm) According to ASTM D256-56.

(4) Weather resistance (%) It is shown by the retention rate of Izod impact strength after exposure for 500 hours under the condition of ASTM D1435 with a UV carbon arc weather meter.

(4) Surface gloss (%) According to ASTM D523.

Example 1 Was dissolved in 900 g of n-hexane and stirred until uniform.

Next, 5 g of potassium oleate as a surfactant is added to 90
After dispersing to 0 g, 60% with the solution using a homomixer
The mixture was mixed for 1 minute (rotation speed of stirring blade: 12000 rpm).

N-Hexane was distilled off from the obtained emulsion at a temperature of 60 to 80 ° C to obtain a latex.

In the latex thus obtained, 0.5 part by weight of p-divinylbenzene per 100 parts by weight of rubber 1,1-di-t-butylperoxy 3,3,5-trimethylcyclohexane (peroxide (A)) 0.5 One part by weight was added and well dispersed.

The latex is then transferred to an autoclave and flushed with nitrogen for 3K.
The latex composition of the present invention was obtained by heating at 120 ° C. for 2 hours under a pressure of g / cm ² G and crosslinking.

The properties of this latex composition and the properties of the thermoplastic polymer obtained from the composition as described above are shown in Table 2 below.

Example 2 Example 1 was repeated except that EPT (A) was changed to 92 g and polybutadiene A was changed to 8 g.

Example 3 Example 1 was repeated except that EPT (A) was 87 g, polybutadiene A was 13 g, and peroxide (A) was 0.7 parts by weight.

Example 1 was repeated except that EPT (A) was 83 g, polybutadiene A was 17 g, modified polyurethane wax was 18 g, and peroxide (A) was 0.7 parts by weight.

Comparative Example 1 Example 1 was repeated except that EPT (A) was 100 g, polybutadiene A was 0 g, and modified polyethylene wax was 10 g.

Comparative Example 2 Example 1 was repeated except that EPT (A) was 75 g and polybutadiene A was 25 g.

Example 5 The procedure of Example 2 was repeated except that polybutadiene B was used instead of polybutadiene A, and the amount of peroxide (A) was 0.3 parts by weight.

Example 6 The procedure of Example 2 was repeated, except that polybutadiene C was used instead of polybutadiene A, and the amount of peroxide (A) was 0.4 parts by weight.

Example 7 Using polybutadiene D instead of polybutadiene A, 20 g of modified polyethylene wax and 0.8 g of peroxid (A) were used.
The same procedure as in Example 2 was carried out except that the amount was parts by weight.

Example 8 The procedure of Example 2 was repeated, except that polybutadiene E was used instead of polybutadiene A, and the amount of peroxide (A) was 0.9 parts by weight.

Example 9 Example 2 except that the modified polyethylene wax was 13 g and no operation for crosslinking (addition of p-divinylbenzene, peroxide (A), heating in an autoclave) was performed.
I went the same way.

Example 10 The procedure of Example 3 was repeated, except that the modified polyethylene wax was 20 g and no operation for crosslinking was performed.

Example 11 72 mol% ethylene unit content, 15 containing 5-ethylidene norbornene unit as a polyene component in iodine value, 135 ° C.
Ethylene with an intrinsic viscosity [η] of 1.2 dl / g in decalin
The procedure of Example 2 was repeated except that a propylene / ethylidene norbornene copolymer rubber was used.

Example 12 Example 2 except that no modified polyethylene wax was added.
I went the same way.

Comparative Example 3 Ethylene unit content 72 mol%, 5-ethylidene norbornene unit as a polyene component containing 15 in iodine value, 135 ° C.
Ethylene with an intrinsic viscosity [η] of 2.2 dl / g in decalin
The procedure of Example 2 was repeated except that a propylene / ethylidene norbornene copolymer rubber was used and no modified polyethylene wax was added.

Comparative Example 4 Ethylene unit content 72 mol%, 5 as Porieren component
Contains 15 ethylidene norbornene units by iodine value, 135
Example 2 was carried out in the same manner as in Example 2 except that an ethylene / propylene / ethylidene norbornene copolymer rubber having an intrinsic viscosity [η] in decalin of 0.5 dl / g was used and the modified polyethylene wax was 20 g.

Claims (2)

[Claims] 1. An ethylene / α-olefin-based amorphous copolymer (A) and the following general formula: In the formula, R represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom. The number average molecular weight of the aliphatic conjugated diene represented by: 500 to 5
000 amorphous polymer (B) in a weight ratio of A: B = 99: 1 to 80:20 and having an average particle diameter of solid content of 0.2 to 3.0 μm.
Latex composition characterized by being in the range of m. 2. The amorphous copolymer (A) component and the amorphous polymer (B) component of the conjugated diene form cross-links within the particles, and these (A) and (B The latex composition according to claim 1, wherein the hot toluene insoluble content of component (b) is in the range of 30 to 95% by weight.