JPH0689232B2 - Polybutylene terephthalate composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polybutylene terephthalate composition having excellent antistatic properties, retention stability during molding and mechanical properties, particularly impact resistance and rigidity. .

[Conventional technology]

Since polybutylene terephthalate resin has excellent mechanical properties, UL electrical properties, heat resistance, etc., it has been widely used in recent years for applications such as mechanical parts and electric equipment parts.

However, while the polybutylene terephthalate resin has the above-mentioned excellent characteristics, the molded product is easily charged due to friction and the like, and has the drawback that dust is likely to adhere to it.
At present, the use is limited particularly in applications requiring antistatic properties.

Until now, various methods have been proposed as a method for imparting antistatic properties to aromatic polyesters. Among them, the methods of using a metal salt of an alkyl sulfonic acid and a polyalkylene glycol in combination (JP-A-52-47072 and JP-A-53-149246) are relatively excellent.

[Problems to be solved by the invention]

However, when the above-mentioned method is applied to the polybutylene terephthalate resin, there is a problem that mechanical properties, particularly rigidity and impact resistance are deteriorated due to poor retention stability during molding.

[Means for solving problems]

Therefore, as a result of intensive studies to solve the above problems, the present inventors have surprisingly used a specific alkyl sulfonic acid metal salt and paraffin wax or olefin wax in combination with a polybutylene terephthalate resin. As a result, they have found that they have excellent antistatic properties as well as excellent mechanical properties when the molding residence time is long, particularly rigidity and impact resistance, and have reached the present invention.

That is, the present invention is based on (A) 100 parts by weight of a polybutylene terephthalate resin having a relative viscosity of 1.30 to 2.00, and (B) 0.01 to 10 parts by weight of an alkylsulfonic acid metal salt represented by the following general formula (I). (In the formula, R is an alkyl group having a carbon number of m, R'is an alkyl group having a carbon number of n (where m and n are m ≧ 2, n ≧ 2, 6 ≦ m +
n is an integer satisfying 30), M is a metal atom, P is the number of charges of the metal M) and (C) Paraffin wax or olefin wax.
The present invention provides a polybutylene terephthalate composition containing 0.01 to 10 parts by weight.

Hereinafter, the constitution of the present invention will be described more specifically.

The (A) polybutylene terephthalate resin used in the present invention means terephthalic acid as an acid component and diol component as a diol component.
It is a polymer obtained by a condensation reaction containing 1,4-butanediol as a component.

If the acid component is 20 mol% or less, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4, Dicarboxylic acids other than terephthalic acid such as 4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid or ester-forming derivatives thereof May be used, if the diol component is 20 mol% or less, ethylene glycol, 1,2-propanediol, 1,3-propanediol,
1,5-pentadiol, 1,6-hexanediol, 1,10-
Decanediol, 1,4-cyclohexanedimethanol,
1,4- such as neopentyl glycol, 2-methyl-1,3-propanediol, polytetramethylene glycol, polyethylene glycol, polypropylene glycol
A diol other than butanediol may be used.

As a polybutylene terephthalate resin, 0.5%
The relative viscosity of the ortho chlorophenol solution of 25 ° C. measured at 25 ° C. needs to be 1.30 to 2.00, and preferably,
It is 1.35 to 1.70. When the relative viscosity of the polybutylene terephthalate resin is less than 1.30, sufficient mechanical strength cannot be obtained, and when it exceeds 2.00, the fluidity at the time of molding becomes poor, which is not preferable either.

The metal salt of alkyl sulfonic acid (B) used in the present invention has the following general formula: (In the formula, R and R'are respectively alkyl groups having carbon numbers m and n, M is a metal atom, P is the number of charges of the metal M, and m and n are integers satisfying the following conditions. 2, n ≧
2,6 ≦ m + n ≦ 30). ) R and R'may have straight or branched alkyl groups, and the sum of carbon numbers of R and R '(m +
n) is 6 to 30, preferably 10 to 20. The compound of formula (I) may be a single compound or a mixture of different compounds.

Preferred examples of M include alkali metals and alkaline earth metals, of which lithium, sodium and potassium are more preferred, and sodium is particularly preferred.

Preferred specific examples of the compound represented by the formula (I) include:
The compound of the following general formula may be mentioned.

Of the compounds represented by the general formulas (II) to (IV), compounds having m + n (the number of carbon atoms of the alkyl group bonded to C adjacent to S) of 12 to 16 are particularly preferable.

In the present invention, when R or R ′ has 1 or less carbon atoms, that is, when the metal sulfonate group is present at the terminal of the alkyl group or at the β-position, the antistatic property is not exhibited when added to the polybutylene terephthalate resin. Further, when the sum (m + n) of the carbon numbers of both is less than 6, the mechanical properties of the polybutylene terephthalate resin tend to be deteriorated, while when it exceeds 30, the antistatic effect tends to be deteriorated. Not preferable.

The amount of the alkyl sulfonic acid metal salt added is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.5 to 3 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin.
Parts by weight. If the addition amount is less than 0.01 parts by weight, the effect of improving the antistatic property is not recognized, and if it exceeds 10 parts by weight, the mechanical properties of the polybutylene terephthalate resin tend to deteriorate, which is not preferable.

Other antistatic agents (such as sodium dodecylbenzene sulfonate, sodium linear alkyl sulfonate, aryl metal hypophosphite, etc., provided that 50% by weight or more of the total amount of the antistatic agent is the alkyl sulfonate metal salt of the present invention. Salt, etc.) may be used together.

The (C) paraffin wax or olefin wax used in the present invention is a petroleum wax or olefin polymer or wax by-product which is solid at room temperature, such as polyethylene wax, polypropylene wax, montanic acid wax. Examples of the waxes (esters, half-esters, salts), waxes marketed under the names of 130 ° F waxes, crostarin waxes, etc. are montan waxes or carboxyl groups, hydroxyl groups, esters having a number average molecular weight of 300 or more. Polyethylene waxes having functional groups such as groups are preferred. Further, two or more kinds of the above paraffin wax or olefin wax may be mixed and used. The paraffin wax or olefin wax may be used in advance by mixing with the (B) metal salt of alkylsulfonic acid.

The content of paraffin wax or olefin wax in the present invention is 100% polybutylene terephthalate resin.
It is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight with respect to parts by weight. If it is less than 0.01 parts by weight, the moldability is not sufficiently improved, and if it exceeds 10 parts by weight, the mechanical properties tend to be impaired, which is not preferable.

Although not particularly required in the composition of the present invention, an ethylene polymer can be added. The ethylene-based polymer is preferably an ethylene-based polymer having a number average molecular weight of 10,000 or more, such as low-density polyethylene, high-density polyethylene and ethylene-based copolymer.

The ethylene copolymer may be a random copolymer, a block copolymer, a graft copolymer, or the like.

As a copolymer component in the ethylene-based copolymer, α-olefin having 3 or more carbon atoms (eg, propylene, butene-1), non-conjugated diene (eg, norbornadiene,
Ethylidene norbornene, etc.), vinyl ester (eg vinyl acetate etc.), α, β-unsaturated acids such as acrylic acid and methacrylic acid and their esters (eg ethyl acrylate, methyl methacrylate etc.), maleic anhydride, maleimide etc. Among them, glycidyl ester of α, β-unsaturated acid represented by the following general formula (I) is preferable.

(In the formula, R ″ is a hydrogen atom, a lower alkyl group or a lower alkyl group substituted with a glycidyl ester group.) Specific examples of the compound represented by the formula (V) include glycidyl acrylate, glycidyl methacrylate and ethacryl. Glycidyl acid, glycidyl itaconate and the like, of which glycidyl methacrylate can be preferably used.

Two or more of the above copolymer components may be used in combination, and the ratio of the copolymer component in the ethylene polymer is 0.1 to 50% by weight, preferably 0.5 to 30% by weight.

Preferred examples of the ethylene-based polymer include high-density polyethylene powder, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g-maleic acid water copolymer, ethylene / ethyl acrylate-g- Maleic anhydride copolymer, ethylene / propylene / ethylidene norbornene-g-maleic anhydride copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, ethylene /
Glycidyl acrylate polymers, etc., among which, in general, high-density polyethylene powder having a number average molecular weight of 100,000 or more, ethylene / glycidyl methacrylate copolymer,
Ethylene / vinyl acetate / glycidyl methacrylate copolymers and mixtures thereof are more preferably used.

When the ethylene-based polymer is added in the present invention, it is preferable to use 50 parts by weight or less, particularly 40 parts by weight or less because the addition amount thereof tends to impair the mechanical properties of the polybutylene terephthalate resin if it is too large. Is preferred.

Although not particularly essential, antistatic property and handleability can be improved by using a finely powdered inorganic silicon compound together in the present invention.

Examples of the finely divided inorganic silicon compound that can be used in the present invention include silicic acid anhydride (silica), simple silicates, silica / alumina bonded substances, alumino acid salts, and the like, but are not particularly limited, but silicon dioxide is preferable. Is preferred. The fine powdery anhydrous silicon compound preferably has an average particle size of 30 μm or less,
It is more preferably 1 μm or less, still more preferably 0.2 μm or less. Silicon dioxide that can be used in the present invention may optionally contain anhydrous or hydrated forms, such as silicic acid,
It may be a synthetically manufactured product commercially available under the name “Aerosil” (manufactured by Aerosil). The silicon compound of the present invention may be used as a mixture with (B) metal salt of alkyl sulfonic acid in advance.

The amount of the silicon compound added is preferably 0.001 to 100 parts by weight of the polybutylene terephthalate resin.
5 parts by weight, more preferably 0.05 to 2 parts by weight.

In the composition of the present invention, an inorganic filler can be added, though it is not essential. The inorganic filler may be in any form such as fibrous and granular, and specifically, glass fiber, carbon fiber, metal fiber, asbestos, wollastonite, potassium whisker titanate, clay, mica, bentonite, glass beads, titanium oxide, Examples thereof include calcium carbonate, barium sulfate, gypsum, aluminum oxide, titanium oxide, talc, and the like, and preferred is a strand of glass fiber of the chopped strand type. The addition amount of the inorganic filler is 150 parts by weight or less, preferably 100 parts by weight or less, based on 100 parts by weight of the polybutylene terephthalate resin. Addition amount is 150
If it exceeds the weight part, the mechanical properties of the polybutylene terephthalate resin tend to be impaired, which is not preferable.

In the composition of the present invention, rigidity, dimensional accuracy, etc. can be improved by adding the above-mentioned inorganic filler. Generally, when an antistatic agent is present, the effect of improving the rigidity when an inorganic filler is added is small, but such a tendency is not observed in the composition of the present invention.

The heat stabilizer (eg hindered phenol, phosphorus compound etc.), weathering agent and UV absorber (eg various resorcinol, salicylate, benzotriazole, etc.) within the range not impairing the object of the present invention for the composition of the present invention. Benzophenone) lubricants and mold release agents (eg stearic acid and its salts, esters, half esters,
Stearyl alcohol, stearamide, etc.), dyes, colorants including pigments, flame retardants, flame retardant aids, and crystallization accelerators can be added one or more of the usual additives.

The method for producing the composition of the present invention is not particularly limited, but preferably a polybutylene terephthalate resin, an alkylsulfonic acid metal salt, paraffin wax or olefin wax, if necessary, an ethylene polymer, and finely divided inorganic silicon. A method of melt-kneading the compound and the like using an extruder can be mentioned.

〔Example〕

The effects of the present invention will be described in more detail below with reference to examples.
In addition, the part in an Example shows a weight part.

Examples 1-5, Comparative Examples 1-3 Polybutylene terephthalate (A) 100 having a relative viscosity of 1.46
Parts, the type and amount of the antistatic agent (B), polyethylene wax (C) and, for some, ethylene / glycidyl methacrylate copolymer (D) and / or silicic acid powder (E) was dry blended and melt-mixed and pelletized by a screen extruder set at 250 ° C. Next, the obtained pellets are heated at 250 ° C.
Using a 5 ounce screw-in-line type injection molding machine set to 3 mm x 60 mm x 60 mm square plate, ASTM No. 1 dumbbell, 1/4 "Izod impact test piece, molding cycle injection (second) / cooling (second) ) 15/20 (molding cycle (a) or 1
It was created at 5/200 (molding cycle (b)). Using these test pieces, a tensile test (ASTM D-638) and an Izod impact test with V-notch (ASTM D-256) are performed (impact strength).
Along with, the resistivity of the square plate molded product using a super insulation resistor,
Charge decay half-life (time required for this charge to decay to half the initial value after applying 8,000 V of charge for 120 seconds (half-life)
Was measured. The results are shown in Table-1.

As is clear from the results in Table 1, the polybutylene terephthalate resin, the composition of the present invention added in combination with the alkylsulfonic acid metal salt and paraffin wax or olefin wax has a surface resistivity, From the comparison of antistatic property represented by charge decay half-life and physical properties in molding cycle (a) and molding cycle (b), it is represented by stagnant flow stability, tensile strength and Izod impact strength with V-notch. It can be seen that the mechanical properties are balanced and excellent. Furthermore, by using an ethylene polymer and a finely powdered inorganic silicon compound together, the antistatic property is further improved, and the impact resistance represented by Izod impact strength with V-notch and the rigidity represented by tensile strength are balanced. It can be seen that a polybutylene terephthalate resin composition having a good combination can be obtained.

When no paraffin wax or olefin wax is used as in Comparative Example 1, and when the charge decay half-life is long and the antistatic property is poor, the molding cycle (a),
From the comparison of the tensile strength and the Izod impact strength of (b), it can be seen that the stagnant stability is also inferior.

In Comparative Example 2 in which the polyethylene wax was excessively blended,
It had a long half-life of static charge decay, poor antistatic properties, and poor mechanical properties represented by tensile strength and Izod impact strength.

Comparative Example 3 in which an alkyl sulfonic acid metal salt having a structure other than the structure defined in the present invention was used was found to be significantly inferior in stagnant stability from the comparison of the data shown in molding cycles (a) and (b). I knew it was.

Example 6 and Comparative Examples 4 to 5 Processing and physical property evaluations were carried out in the same manner as in Example 3 except that 30% by weight of the stranded glass fiber having a fiber length of 3 mm was added to Example 3. 6).

For comparison, 30% by weight of the same glass fiber as in Example 6 was added to the composition excluding the metal alkyl sulfonate (Comparative Example 4) and the composition having a different antistatic agent (Comparative Example 3). The composition (Comparative Example 5) was also evaluated, and the results are shown in Table-2.

From the results shown in Table 2, even when glass fibers are blended, the composition of the present invention is not only excellent in antistatic property and molding retention stability, but also a molded product having more excellent mechanical properties can be obtained. It is clear that

[Effects of the Invention] From the aromatic polyester composition of the present invention, molded articles having excellent antistatic properties, molding retention stability and mechanical properties, particularly impact resistance and rigidity, can be used for injection molding, extrusion molding, etc. Since it can be easily obtained by a molding method, it is useful as a material for various parts.

Claims (1)

[Claims] 1. (A) 0.01 to 10 parts by weight of an alkyl sulfonic acid metal salt represented by the following general formula (I) with respect to 100 parts by weight of a polybutylene terephthalate resin having a relative viscosity of 1.30 to 2.00. (In the formula, R is an alkyl group having a carbon number of m, R'is an alkyl group having a carbon number of n (where m and n are m ≧ 2, n ≧ 2, 6 ≦ m +
n is an integer satisfying 30), M is a metal atom, P is the number of charges of the metal M) and (C) Paraffin wax or olefin wax.
A polybutylene terephthalate composition containing 0.01 to 10 parts by weight.