JPH06116480A - Elastomer composition - Google Patents

Abstract

PURPOSE:To provide an elastomer composition which is excellent in antistatic properties and molding surface appearance and is extensively usable. CONSTITUTION:The elastomer composition mainly consists of a block copolymer elastomer obtained by using 10-90wt.% hard segment comprising a polyamide component and/or a polyester component and 90-10wt.% soft segment comprising poly(alkylene oxide) glycol component in the presence of a lithium compound and contains 10-50,000ppm (in terms of the lithium atoms) of the lithium compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastomer composition having excellent antistatic performance and surface appearance of molded articles.

[0002]

2. Description of the Related Art Conventionally, a block copolymer having a polyamide component as a hard segment and polyethylene glycol as a soft segment has been used in a wide range of fields as a thermoplastic elastomer (polyamide elastomer). This polyamide elastomer has the characteristics that its surface resistivity is lower than that of styrene resins such as ABS resin and impact-resistant polystyrene, and that it has excellent antistatic performance. However, the antistatic performance of this material is not sufficient depending on the field in which it is used, and is not sufficient in fields such as IC related fields that require high antistatic performance, and its field of use is limited.

[0003]

SUMMARY OF THE INVENTION The present invention has been made against the background of the above-mentioned problems of the prior art, and it is an object of the present invention to provide an elastomer composition which is excellent in antistatic performance and surface appearance of molded articles and can be widely used. To aim.

[0004]

According to the present invention, 10 to 90% by weight of a hard segment consisting of (A) a polyamide component and / or a polyester component, and (B) a soft segment consisting of a poly (alkylene oxide) glycol component are contained. 10% by weight and a block copolymer elastomer obtained by production in the presence of a lithium compound as a main component, wherein the lithium compound is 10 to 50 in terms of lithium atom in the composition. 1,000 ppm
It is intended to provide an elastomer composition containing the same.

The block copolymer elastomer used in the present invention is a block copolymer having a polyamide and / or polyester component as a hard segment and a poly (alkylene oxide) glycol component as a soft segment.

The polyamide component used as the (A) hard segment is not particularly limited and includes, for example, ethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,3,4 or 2,4. Aliphatic and alicyclic compounds such as 4-trimethylhexamethylenediamine, 1,3 or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexyl) methane, m-xylylenediamine and p-xylylenediamine Or a polyamide derived from an aromatic diamine and an aliphatic, alicyclic or aromatic dicarboxylic acid such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid or isophthalic acid; caprolactam, laurolactam, etc. Lactam Polyamides obtained by ring-opening polymerization of amides; polyamides derived from aminocarboxylic acids such as ω-aminocaproic acid, ω-aminoenoic acid, aminoundecanoic acid and 12-aminododecanoic acid; copolyamides thereof; and mixtures thereof Examples include polyamide. The preferred polyamide component is nylon 6,
Nylon 6,6.

The polyester component used as the other (A) hard segment includes polycondensation of a dicarboxylic acid compound and a dihydroxy compound, polycondensation of an oxycarboxylic acid compound, ring-opening polycondensation of a lactone compound, or a polycondensation thereof. It is a polyester obtained by polycondensation of a mixture of each component, and both homopolyesters and copolyesters can be used in the present invention.

Of these, the dicarboxylic acid compound is
Examples thereof include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid and sebacic acid, and alkyl, alkoxy or halogen substitution products thereof. In addition, these dicarboxylic acid compounds can also be used in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. These dicarboxylic acid compounds may be used alone or in combination of two or more.

Examples of dihydroxy compounds include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, butenediol, hydroquinone, resorcin, dihydroxydiphenyl ether, cyclohexanediol, and 2,2-bis (4-hydroxyphenyl) propane. Also included are polyoxyalkylene glycols and their alkyl, alkoxy or halogen substituents. These dihydroxy compounds can be used alone or in combination of two or more.

Further, examples of the oxycarboxylic acid compound include oxybenzoic acid, oxynaphthoic acid, diphenyleneoxycarboxylic acid, and the like.
Also included are alkoxy and halogen substitutes. These oxycarboxylic acid compounds can be used alone or in combination of two or more kinds.

Further, as the lactone compound, ε-caprolactone and the like can be mentioned. Preferred polyester components include polybutylene terephthalate and polyethylene terephthalate.

The molecular weight of the component (A) is not particularly limited, but in the case of a polyamide elastomer, the reduced viscosity (η _{sp / c} ) (in a formic acid solution, 0.5 g / 100 ml, 25
0.5-3.0 is preferable. Also,
When the component (a) is a polyester elastomer, the intrinsic viscosity [η] (o-chlorophenol, measured at 35 ° C)
Is preferably 0.5 to 2.5.

The component (A) used in the present invention is 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 30 to 80% by weight in the elastomer.
If it is less than 10% by weight, the surface appearance of the molded product is poor, while 90% by weight.
If it exceeds, the antistatic performance is poor.

Next, the component (B) constituting the elastomer used in the present invention is poly (alkylene oxide).
As the glycol component, polyethylene glycol, poly (1,2 or 1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol,
Poly (hexamethylene oxide) glycol, a block or random copolymer of ethylene oxide and propylene oxide, a block or random copolymer of ethylene oxide and tetrahydrofuran, and the like can be mentioned. These ends can be aminated, carboxylated or epoxidized. You may use. Among these components (B), polyethylene glycol is preferable from the viewpoint of antistatic property.

The molecular weight of the component (B) is 2 in terms of number average molecular weight.
00-20,000-preferably 300-10,000
It is 0, more preferably 300 to 4,000. The component (B) used in the present invention is 90 to 90% in the elastomer.
It is 10% by weight, preferably 80 to 20% by weight, and more preferably 70 to 20% by weight. If it exceeds 90% by weight, the surface appearance of the molded article will be poor, while if it is less than 10% by weight, the antistatic performance will be poor.

The block copolymer elastomer used in the present invention can be produced by using a known polymerization method and a known polymerization catalyst. The preferred polymerization method is melt polymerization. As a specific example, after polymerizing the polyamide component as the component (A), a dicarboxylic acid compound is added to make both ends of the polyamide component a carboxylic acid, and polyethylene glycol as the component (B) is added and polymerized to obtain a polyamide elastomer. A method for obtaining a polyamide-forming component, an excess dicarboxylic acid compound, and a method for obtaining a polyamide elastomer by batch-adding and polymerizing a predetermined amount of polyethylene glycol, in a method for producing a polyamide elastomer, by producing the polyamide component in place of the polyester component, Examples thereof include a method of obtaining a polyester elastomer.
The above block copolymer elastomers may be used alone or in combination of two or more.

Next, examples of the lithium compound used in the present invention include LiCl, LiBr, LiI and LiS.
CN, LiBF ₄ , LiAsF ₆ , LiClO ₄ , Li
CF ₃ SO ₃ , LiC ₆ F ₁₂ SO ₃ , LiHgI ₂ , L
iAlH ₄ , LiBH ₄ , Li ₂ CO ₃ , Li ₃ C ₆ H
_{5 O 7 · 4H 2 O,} LiF, LiOH · H 2 O, LiN
O ₃ , Li ₃ PO ₄ , Li ₂ SO ₄ · H ₂ O, LiB ₄
In addition to an inorganic compound such as O ₇ , a lithium salt of an organic compound having an acid group such as a carboxyl group, a phenol group, a sulfonic acid group, a phosphoric acid group, and a phosphorous acid group can be used. Examples of these include lauric acid. Examples thereof include lithium, lithium stearate, and lithium rosinate. Among these lithium compounds, preferred lithium compounds are lithium hydroxide (LiOH.H ₂ O) and lithium chloride (LiCl). The lithium compounds may be used alone or in combination of two or more.

This lithium compound must be present during the production of the block copolymer elastomer used in the present invention, and the object of the present invention can be achieved even if it is added to an injection molding machine when the elastomer is molded. It is not possible. Here, in order to produce a block copolymer elastomer in the presence of a lithium compound, separation of the elastomer before, during, or after the polymerization of the elastomer is performed.
The lithium compound may be added all at once or in portions before recovery. As a method of adding the lithium compound, the lithium compound may be added as it is, may be dissolved in the polymerization component in advance, and may be added in the form of another solvent.

The amount of the lithium compound used is 1 in terms of lithium atom in the block copolymer elastomer of the present invention.
0 to 50,000 ppm, preferably 10 to 5,000
ppm, and more preferably 50 to 1,000 ppm. If the amount used is less than 10 ppm, the antistatic performance will be poor, while if it exceeds 50,000 ppm, the surface appearance of the molded product will be poor.

The elastomer composition of the present invention (hereinafter sometimes referred to as "elastomer composition (I)") has excellent antistatic properties and the surface appearance of molded articles, but other materials may be used depending on the required performance. A thermoplastic resin (hereinafter sometimes referred to as "other thermoplastic resin (II)") may also be blended and used. Examples of other thermoplastic resins include ABS resin, AES resin, AS resin, MBS resin, A
AS resin, MS resin, HIPS, styrene resin such as polystyrene, olefin resin such as polyethylene and polypropylene, polyamide resin, thermoplastic polyethylene resin, polyacetal, polycarbonate, polysulfone, polyether sulfone, polyphenylene ether, polyphenylene sulfide, liquid crystal polymer , Vinylidene fluoride polymer, ethylene-vinyl acetate copolymer, and the like. These can be used alone or in combination of two or more kinds.

The other thermoplastic resin is preferably a styrene resin or an olefin resin, more preferably a styrene resin. Among these styrene resins, those obtained by polymerizing an aromatic vinyl compound or a monomer component composed of an aromatic vinyl compound and another monomer in the presence or absence of a rubbery polymer are particularly preferable.

Here, as the rubbery polymer, polybutadiene, styrene-butadiene copolymer (styrene content is preferably 5 to 60% by weight), styrene-isoprene copolymer, acrylonitrile-butadiene copolymer, ethylene-α. -Olefin copolymer, ethylene-α-olefin-polyene copolymer, acrylic rubber, butadiene-
Examples thereof include acrylic copolymers, polyisoprene, styrene-butadiene block copolymers, styrene-isoprene block copolymers, hydrogenated styrene-butadiene block copolymers, hydrogenated butadiene-based polymers, and ethylene-based ionomers. Among them, the styrene-butadiene block copolymer and the styrene-isoprene block copolymer include those having an AB type, ABA type, taper type, or radial teleblock type structure. Further, the hydrogenated butadiene-based polymer is a hydrogenated product of the block copolymer, as well as a styrene polymer and a styrene-polymer.
Hydrogenated product of block with butadiene random copolymer,
A hydrogenated product of a block polymer composed of a block having a 1,2-vinyl bond in the butadiene portion of 20% by weight or less and a polybutadiene having a 1,2-vinyl bond of more than 20% by weight can be used. The amount of the rubbery polymer used is not particularly limited, but is preferably 3 to 70% by weight in the styrene resin.
Is.

As the aromatic vinyl compound, styrene, α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, pt-butylstyrene, ethylstyrene, Vinyl naphthalene, o-methyl styrene, dimethyl styrene, etc.
It is also possible to use two or more species together. Among these aromatic vinyl compounds, styrene is preferably used as the aromatic vinyl compound. Even when two or more aromatic vinyl compounds are used in combination, it is preferable to use styrene in a proportion of 40% by weight or more.

Other monomers copolymerizable with this aromatic vinyl compound include vinyl cyan compounds such as acrylonitrile and methacrylonitrile, methyl acrylate,
Acrylic alkyl esters such as ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and methyl methacrylate such as methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate and cyclohexyl methacrylate. Maleimide compounds such as esters, maleimides, N-methylmaleimides, N-ethylmaleimides, N-phenylmaleimides, N-cyclohexylmaleimides, epoxy group-containing unsaturated compounds such as glycidyl methacrylate, allyl glycidyl ether, acrylic acid, methacrylic acid, itacone Acid, unsaturated acid such as maleic acid, maleic anhydride, itaco anhydride Acids, unsaturated carboxylic acid anhydrides such as citraconic anhydride, acrylamine, aminoethyl methacrylate, aminopropyl methacrylate, amino group-containing unsaturated compounds such as aminostyrene, 3-hydroxy-1-propene, 4-hydroxy- 1-butene, cis-
4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl-1-propene, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and other hydroxyl group-containing unsaturated compounds, and Acrylamide, vinyl oxazoline, etc. are mentioned, and these compounds are used by 1 type (s) or 2 or more types.

The above-mentioned monomer component (aromatic vinyl compound or aromatic vinyl compound and other vinyl monomer copolymerizable therewith) is preferably an aromatic vinyl compound and cyanide from the viewpoint of impact resistance. It is a monomer mixture composed of a vinyl compound, and a preferable ratio is aromatic vinyl compound / vinyl cyanide compound = 80-60 / 20-4.
It is 0% by weight. (Co) polymers of aromatic vinyl compounds and other monomers include those polymerized in the presence of the rubbery polymer and those polymerized in the absence thereof, but they may be used as a mixture. It can be used alone or can be used alone.

The styrene resin used in the present invention is produced by emulsion polymerization, solution polymerization, suspension polymerization or the like of the above monomer component in the presence or absence of a rubbery polymer. At this time, as the polymerization initiator, molecular weight regulator, emulsifier, dispersant, solvent, etc. used for the polymerization,
It is possible to use those used in these polymerization methods as they are. As a preferred method of producing a styrene resin, a monomer component consisting of an aromatic vinyl compound (and other monomer) and an additional emulsifier in the presence of a rubbery polymer obtained by emulsion polymerization, Using a polymerization initiator, the polymerization temperature is generally 30 to 150 ° C., the polymerization time is 1 to 15
Emulsion polymerization or solution polymerization with a graft copolymer (including ungrafted vinyl-based polymer) obtained by graft copolymerization under conditions of time and polymerization pressure of -1.0 to 5.0 kg / cm ^2. It is produced by mixing with the vinyl polymer obtained by.

The styrene-based resin is preferably one obtained by graft-polymerizing the monomer component in the presence of the rubber-like polymer as described above, from the viewpoint of impact resistance. In this case, the graft ratio is preferably 20 to 200% by weight. The intrinsic viscosity (measured in methyl ethyl ketone at 30 ° C.) of the styrene-based resin soluble in methyl ethyl ketone is 0.3 to 1.
5 is preferable.

When the above-mentioned other thermoplastic resin (II) is blended with the elastomer composition (I) of the present invention, the blending ratio is from the viewpoint of balance of antistatic property, impact resistance, rigidity and the like. , (I) / (II) = 2 to 60/98 to 40% by weight is preferable.

The elastomer composition (I) of the present invention
When other thermoplastic resin (II) is blended with, a compatibilizer that improves the compatibility between the component (I) and the component (II) can be used. As a preferable compatibilizing agent, styrene obtained by copolymerizing a vinyl-based monomer having a functional group such as a hydroxyl group, an epoxy group, a carboxyl group, an acid anhydride group, an amino group and an oxazoline group in a part of the styrene resin. Examples thereof include a system resin or a copolymer of an α-olefin and the functional group-containing vinyl monomer. Of these functional groups, an epoxy group, a carboxyl group and a hydroxyl group are preferable, and a hydroxyl group is particularly preferable.

When a compatibilizing agent containing such a functional group is used, an aromatic vinyl compound and (meth) acrylic acid alkyl ester and / or vinyl cyanide are used as the monomer component in the styrene resin. It is preferable to use a compound obtained by combining the functional group-containing vinyl monomer with the compound. The copolymerization amount of the functional group-containing vinyl monomer is 0.5 to 30% by weight in the styrene resin. In addition, the amount of the functional group-containing vinyl monomer used is
In the composition comprising the components (I) to (II), preferably,
It is 5 to 30% by weight, preferably 1 to 25% by weight.

When the elastomer composition of the present invention or the composition comprising the components (I) to (II) (hereinafter collectively referred to as "composition" in some cases) is used, glass fiber and carbon are used. Fiber, metal fiber, glass beads, glass powder, wollastonite, rock filler, calcium carbonate, talc, mica, glass flakes, kaolin, barium sulfate, graphite, molybdenum disulfide, magnesium oxide, zinc oxide whiskers, potassium titanate whiskers Fillers such as can be used alone or in combination. Among these fillers, glass fibers and carbon fibers preferably have a fiber diameter of 6 to 60 μm and a fiber length of 30 μm or more. These fillers are used in an amount of about 2 to 150 parts by weight based on 100 parts by weight. In addition, other known antibacterial / antifungal agents, flame retardants, antioxidants, plasticizers, colorants, lubricants and the like can be added to the composition of the present invention as additives.

The composition of the present invention can be obtained by kneading the components using various extruders, Banbury mixers, kneaders, rolls and the like, preferably an extruder. When kneading each component, each component may be kneaded together or may be kneaded by a multi-stage addition method. The composition of the present invention can be made into various molded articles by injection molding, sheet extrusion, vacuum molding, profile molding, foam molding and the like. Molded articles obtained in this way utilize the excellent properties of various parts of home appliances,
It is useful for housings, electric / electronic fields, various parts in the automotive field, housings, and miscellaneous goods.

[0033]

EXAMPLES The present invention will be described more specifically below with reference to examples. In the examples, parts and% are based on weight unless otherwise specified. In addition, various measurements in the examples were measured according to the following.

Antistatic surface specific resistance: A disk having a diameter of 100 mm and a thickness of 2 mm was molded and conditioned at 23 ° C. × 50% relative humidity for 7 days, and then 432 manufactured by Yokogawa Hewlett-Packard Co.
The surface resistivity was measured using a 9A type super insulation resistance meter. Charged voltage A 40 mm × 40 mm test piece was cut out from the disk, and the applied voltage was measured for 30 seconds at an applied voltage of 10 kV using a static Honest meter manufactured by Shishido Electrostatic Co., Ltd., and the charged voltage was measured.

Surface appearance of molded product A flat plate was molded using an injection molding machine, and the surface appearance of the molded product was visually evaluated according to the following evaluation criteria. ◯: Smooth and good ×: Molded product surface had unevenness, unevenness, etc., and poor impact resistance According to ASTM D256, the Izod impact strength was measured at a thickness of ¼ ″, notched and at 23 ° C.

Reference Example (Preparation of Each Component) Polymer (a) -1 After obtaining a polymer block of nylon 6 by ring-opening polycondensation of ε-caprolactam, carboxylic acids were formed at both ends with adipic acid. Polyethylene glycol (PEG1540) having a number average molecular weight of 1,540 and lithium hydroxide were added and polymerized to obtain a polymer (a) -1 which is a polyether ester amide elastomer. The ratio of the polyamide component of the polymer (a) -1 to the polyethylene glycol component is about 5
0/50 (%), using formic acid at 25 ° C, concentration 0.5
The reduced viscosity measured in g / 100 ml was 1.8.
The melting point of the polymer measured by DSC (differential thermal analysis) was 205 ° C.

Polymer (a) -2 to (a) -11 In the method for producing polymer (a) -1, the polymer (a) is prepared by changing the amounts of hard segment, soft segment and lithium compound. -2- (a) -11 was obtained. The results are shown in Table 1.

[0038]

[Table 1]

Polymers (b) -1 to 3 were obtained by emulsion polymerization to obtain styrene resins shown in Table 2.

[0040]

[Table 2]

*) Solid content conversion Examples 1 to 8 and Comparative Examples 1 to 5 The above-mentioned various polymers were dried to a water content of 0.1% or less to obtain polymers (b) to 1- (b) -11. Was molded into a test piece for evaluation using an injection molding machine, and the antistatic performance was evaluated by the evaluation method described above. The results are shown in Table 3. The composition with the styrene resin was blended in the blending ratio shown in Table 3, melt-kneaded and pelletized using a twin-screw extruder with a vent.
The obtained pellets are dried to a water content of 0.1% or less,
The antistatic performance and impact resistance were evaluated. Further, Comparative Example 5 shows a polymer (a) -7 kneaded with lithium hydroxide in a twin-screw extruder so as to have a concentration of 100 ppm in terms of lithium atom. The results are also shown in Table 3.

Comparative Example 6 Polymer (a) -1 was prepared by polymerizing in the absence of lithium hydroxide. 12 ppm of lithium hydroxide was mixed with this polymer (a) -12, and the mixture was mixed with a styrene resin in the same manner as in Example 8 and molded, and the evaluation results are shown in Table 3.

[0043]

[Table 3]

As is clear from Table 3, Examples 1-7
Relates to the elastomer composition of the present invention,
Excellent antistatic performance and surface appearance of molded products. In addition, Example 8 is a composition in which a styrene resin is blended with the elastomer composition of the present invention, and it is found that it is excellent in antistatic performance and surface appearance of a molded article, and is also excellent in impact resistance.

On the other hand, in Comparative Example 1, the amount of the lithium compound used was small outside the range of the present invention, and the antistatic performance was poor. Comparative Example 2 is a case where the amount of the lithium compound used is outside the range of the present invention, and the surface appearance of the molded product is inferior. In Comparative Example 3, the amount of hard segment of the elastomer is small outside the range of the present invention, and the amount of soft segment is large outside the range of the present invention, and the surface appearance of the molded product is poor.
Contrary to Comparative Example 3, Comparative Example 4 is an example in which the amount of hard segment is large and the amount of soft segment is small, and the surface appearance of the molded product and the antistatic performance are inferior. Comparative Example 5 is an example in which lithium hydroxide was later added to the polymer (a) -7, and since it was not present during the production of the polymer, the antistatic performance and the surface appearance of the molded product were poor. Comparative Example 6 is an example in which lithium hydroxide was later added to the polymer (a) -12, and since it was not present during the production of the polymer, the antistatic performance and the appearance of the surface of the molded product were poor.

[0046]

EFFECT OF THE INVENTION The elastomer composition of the present invention, or a composition containing another thermoplastic resin mixed therein, is excellent in antistatic performance and surface appearance of molded articles, and is useful for various parts of electric home appliances, housings, and electric / electrical components. It is useful for various parts, housings, miscellaneous goods, etc. in the electronic and automobile fields.

Claims (1)

[Claims] 1. A lithium segment comprising 10 to 90% by weight of a hard segment comprising (A) a polyamide component and / or a polyester component and 90 to 10% by weight of a soft segment comprising (B) a poly (alkylene oxide) glycol component. A composition containing a block copolymer elastomer as a main component, which is obtained by production in the presence of a compound, and which contains a lithium compound in an amount of 10 to 50,000 ppm in terms of lithium atom. object.