JPH09165503A - Polyester resin composition having excellent adhesivity with silicone rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester resin composition capable of strongly adhering to addition-hardening type silicone rubber. SOLUTION: This resin composition is a polybutylene terephthalate resin composition having improved adhesivity and excellent resistance to hydrolysis and resistance to aging and having following composition: 100 pts.wt. of polybutylene terephthalate containing a titanium compound having <=15eq./10<6> g concentration of terminal carboxyl group as a residue of a catalyst, 0.05-3 pts.wt. of a silicon compound having a hydrogen atom directly bonding to at least one silicon atom in one molecule or its polymer, 0.01-0.5 pt.wt. of a phenolic antioxidant and 0.01-0.5 pt.wt. of a thioether-based antioxidant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition capable of firmly adhering to a silicone rubber having excellent durability, particularly hydrolysis resistance and heat aging resistance. In particular, the present invention relates to a technique of applying silicone rubber to the surface of a molded product made of a polyester resin composition and curing the silicone rubber at a temperature lower than the softening temperature of the polyester resin composition to strongly bond the two.

[0002]

2. Description of the Prior Art Thermoplastic polyester resins, especially polybutylene terephthalate, are widely used as industrial resins because of their excellent chemical resistance, heat resistance and mechanical properties. In recent years, with the increasing demands for hydrolysis resistance and heat aging resistance as durability, a silicone rubber that satisfies the above required properties in the electric / electronic field and the automobile field, and has excellent heat resistance, electrical properties, and weather resistance. It is desired to supply an integrally molded body that is firmly bonded.

Conventionally, as a method for adhering an addition-curable silicone rubber and a molded product of an organic resin, for example, a method of applying a primer on the surface of the molded product and curing an uncured silicone material on the resin molded product It has been known.

However, the method of adhering using a primer requires a work step of taking out a molded product once molded from a mold and applying a primer.

Further, the method of applying a self-adhesive silicone rubber material to a molding resin and curing it is such that when a molded article and a silicone rubber are integrally formed using a mold or the like, the silicone rubber itself is There is a big problem that it adheres to the mold. Furthermore, when applied and cured on a synthetic resin molded product, most of the self-adhesive addition-curable silicone rubber materials have sufficient adhesive force for polybutylene terephthalate resin to be used as an integrally molded product. is not.

[0006]

DISCLOSURE OF THE INVENTION The present invention significantly improves the hydrolysis resistance and heat aging resistance of polybutylene terephthalate, which have been increasingly demanded as industrial resin materials for polybutylene terephthalate, and provides polybutylene terephthalate and silicone rubber. To obtain an integrally molded product of a polybutylene terephthalate resin composition and silicone rubber that are adhered to each other with an adhesive strength that can withstand practical use, and to easily and reliably adhere the molded product in a short time to form an integrally molded product. With the goal.

[0007]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems.

That is, in the present invention, a titanium compound is used as a polymerization catalyst and polybutylene terephthalate having a low terminal carboxyl group concentration as a main component, to which a phenolic antioxidant and a thioether antioxidant are added, and a specific compound is further added. A silicon-containing compound and / or a polymer thereof is blended to obtain a molded product of a polybutylene terephthalate resin composition first, and an addition-curable silicone rubber is applied to the surface of the molded product to obtain a conventional addition cure. A molded product is obtained as an integral molded product with a polyester silicone rubber having an adhesive strength that can withstand practical use in a process in which the adhesive strength of the mold silicone rubber is low or cannot be adhered in a short time. In particular, by using an injection molding method, the polybutylene terephthalate resin composition is adhered to the polybutylene terephthalate resin composition under a curing condition for a short time, and the silicone rubber itself can be peeled from a molding die. The present invention has been accomplished by finding the fact that an integrally molded body can be obtained.

That is, the present invention is a technique for improving the adhesion of polybutylene terephthalate, wherein (A) the terminal carboxyl concentration is 15 equivalents / ton or less, and 100 parts by weight of polybutylene terephthalate using a titanium compound as a polymerization catalyst. , (B) 0.05 to 3 parts by weight of a silicon compound and / or a polymer thereof having a hydrogen atom directly bonded to at least one silicon atom in one molecule, (C) a phenolic antioxidant 0.01 ˜0.5 parts by weight and 0.01 to 0.5 parts by weight of the (D) thioether-based antioxidant are blended into the polybutylene terephthalate resin composition.

Polybutylene terephthalate, which is the component (A) of the present invention, contains terephthalic acid as the main acid component,
It is a polyester containing 1,4-butanediol as a main glycol component. Here, "mainly" means occupying 80 mol% or more with respect to all acid components or all glycol components, and preferably 90 mol% or more. As the acid component copolymerizable in the polybutylene terephthalate of the present invention, an aromatic dicarboxylic acid other than terephthalic acid, for example, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, difoxyethane dicarboxylic acid, diphenyl ketone dicarboxylic acid. Examples thereof include acids, diphenylsulfone dicarboxylic acids and the like, aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and the like, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, tetralindicarboxylic acid and decalindicarboxylic acid.

Copolymerizable glycol components other than butanediol include ethylene glycol hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, tricyclodecane dimethylol, xylylene glycol, bisphenol A, bisphenol B,
Examples thereof include bishydroxyethoxybisphenol A.

Further, a compound having a trifunctional or higher functional group within a range in which the polyester does not substantially lose molding performance, for example, glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, etc. It may be polymerized.

The polybutylene terephthalate used in the present invention must use a titanium compound as a polymerization catalyst, and the terminal carboxyl group concentration must be 15 equivalents / 10 ⁶ g or less. When the terminal carboxyl group concentration exceeds 15 equivalents / 10 ⁶ g, the hydrolysis resistance, which is one of the main effects of the present invention, is not significantly improved. Further, when a tin compound is used as a polymerization catalyst, it is not preferable because it inhibits the curing of silicone rubber.

The polybutylene terephthalate used in the present invention has an intrinsic viscosity (a value produced based on a measured value in orthochlorophenol at 35 ° C.) of 0.3 or more, preferably 0.5 or more. Is. This is because when the intrinsic viscosity is lower than this, the mechanical strength is low, and the melt viscosity is low, which makes it difficult to use, and it is meaningless to apply the present invention.

The component (B) used in the present invention is a compound containing at least one silicon per minute or a polymer thereof, and contains the SiH group or vinyl group represented by the following formula (1) or (2). It is a compound.

[0016]

Embedded image

Where m, n, i and j are from 1 to 100
Is an integer. R ^{1 to} R ⁷ are substituted or unsubstituted monovalent hydrocarbons containing no aliphatic unsaturated bond, and are usually groups having 1 to 10 carbon atoms, preferably hydrogen or 1 to 10 carbon atoms. It is the base of 6. As R ^{1 to} R ⁷ ,
Specifically, for example, hydrogen or an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, and a benzyl group; and a cyclo group such as a cyclohexyl group. Alkyl group;
Examples thereof include a chloromethyl group, a cyanoethyl group 3,3,3-trifluoropropyl group and the like in which a part or all of hydrogen atoms of these groups are substituted with a substituent such as a halogen atom and a cyano group. R ^{1 to} R ⁷ may be the same or different. )

The phenolic antioxidant which is the component (C) used in the present invention is a hindered phenol compound.

The phenolic antioxidant is preferably 2,
6-di-t-butyl-p-cresol, 2,2'-methylene-bis- (4-methyl-6-di-t-butylphenol 4,4'-thiobis (3-methyl-t-butylphenol), 1 , 1,3-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] , Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and particularly preferably,
Pentaerythrityl-tetrakis [3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate].

The phenolic antioxidant can be used alone or in combination of two or more. The blending amount of the phenolic antioxidant is required to be 0.01 to 0.5 parts by weight, preferably 0.1 to 1.3 parts by weight, based on 100 parts by weight of the polybutylene terephthalate resin. If the amount is less than 0.01 part by weight, the effect of improving the heat resistance is small and the result is 0.
Even if the amount is more than 5 parts by weight, the effect of improving the heat aging resistance cannot be expected.

Thio which is the component (D) used in the present invention
The ether antioxidant is preferably giteridyl-ti
Odipropionate, tetrakis [methylene-3-
(Dodecylthio) propionate], bis [2-methyl
-4- {3-n-alkyl (C ₁₂Or C₁₄) Thiopropi
Onyloxy} -5-t-butylphenyl] sulfide
It is.

The compounding amount of the thioether type antioxidant is 0.0 with respect to 100 parts by weight of the polybutylene terephthalate resin.
1 to 0.5 parts by weight is necessary, and
0.3 parts by weight is preferred. If the amount is less than 0.01 part by weight, the effect of improving heat resistance cannot be expected.

Further, phosphorus-based antioxidants that are widely used as antioxidants should not be used because they inhibit the curing of silicone rubber.

The polybutylene terephthalate resin composition of the present invention may further contain a reinforcing material such as glass fiber, an inorganic filler, a pigment, a flame retardant, a flame retardant aid, a crystal nucleating agent and a light stabilizer. it can.

The addition-curable silicone rubber composition, which is the object of improving the adhesiveness of the polybutylene terephthalate resin composition of the present invention, is a vinyl compound-containing organopolysiloxane and an organohydrogenpolysiloxane that uses a platinum compound as a catalyst. It is cured by an addition reaction.

The vinyl group-containing organopolysiloxane is
At least 2 vinyl groups bonded to silicon atoms in one molecule
I have one. The molecular structure of the vinyl group-containing organopolysiloxane may be linear or branched, and even if the vinyl group exists only at the terminal of the molecule, it may be in the middle of the molecular chain. It may be present only at the end of the molecule or in the middle of the molecular chain. In particular, it can be represented by the following general formula (2).

[0027]

Embedded image

The vinyl-containing organopolysiloxane is
Viscosity at 25 ° C is 10 to 1,000,000 cSt
(Centistokes) is preferable, and further 1
It is preferable that it is from 00 to 10,000 cSt.
The vinyl group-containing organopolysiloxane can be produced by a method known per se.

The organohydrogenpolysiloxane has at least two hydrogen atoms bonded to silicon atoms in one molecule. This component acts as a crosslinking agent, and the composition of the present invention is cured by the addition reaction between the hydrogen atom bonded to the silicon atom and the vinyl group of the vinyl group-containing polysiloxane. .

The molecular structure of this organohydrogenpolysiloxane is not particularly limited, and linear, branched, or cyclic structures can be used. The viscosity of this organohydrogenpolysiloxane at 25 ° C is usually 0.5 to 1000 cSt, preferably 1 to 200 cSt.

Examples of the organohydrogenpolysiloxane include the following average composition formula:

[0032]

Embedded image H _a (R ⁸ ) _b SiO _{(4-ab) / 2} (wherein R ⁸ is a substituted or unsubstituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, and a and b Is 0 <a <
It is a number that satisfies 2, 1 ≦ b ≦ 2 and 2 ≦ a + b ≦ 3. ) Are suitably used.

A substituted or unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond represented by R ⁸ in the above average composition formula, which is usually a group having 1 to 10 carbon atoms, preferably 1 to It is the base of 7. Specific examples of R ⁸ include the above 1
The groups exemplified as ~ 7 are similarly exemplified.

Further, a and b are 0 <a <2,
It is a number satisfying 1 ≦ b ≦ 2 and 2 ≦ a + b ≦ 3, preferably 0.3 ≦ a ≦ 1 and 2 ≦ a + b ≦ 2.7.

The component organohydrogenpolysiloxane can be produced by a method known per se, and is usually R ⁸ SiHCl ₂ , R ⁸ ₃ SiCl, R ⁸ ₂ SiC.
It can be produced by hydrolyzing chlorosilane such as l ₂ or R ⁸ ₂ SiHCl, or by equilibrating the siloxane obtained by such hydrolysis.

Specific examples of the organohydrogenpolysiloxane include compounds represented by the following formula.

[0037]

Embedded image

The amount of the organohydrogenpolysiloxane compounded is not particularly limited, but one vinyl group bonded to the silicon atom contained in the vinyl group-containing organopolysiloxane is bonded to the silicon atom of the organohydrogenpolysiloxane. It is preferable to mix the amount so that the number of hydrogen atoms is 1 to 5.

The platinum compound as the addition reaction catalyst is used to promote the addition reaction between the vinyl group and the hydrogen atom bonded to the silicon atom of the organohydrogenpolysiloxane.

As the platinum compound, those which are usually used as an addition reaction catalyst for the organopolysiloxane composition can be used. Specifically, simple platinum, for example, H ₂ PtCl ₆ · XH ₂ O, NaH
PtCl ₆ · XH ₂ O, KHPtCl ₆ · XH ₂ O, N
a ₂ PtCl ₆ · XH ₂ O, K ₂ PtCl ₆ · XH
₂ O, PtCl ₄ · XH ₂ O, PtCl ₂ , Na ₂ Pt
Examples thereof include platinum compounds such as Cl ₄ .XH ₂ O and H ₂ PtCl ₄ .XH ₂ O (where X is a positive integer). Further, a complex of the platinum compound with, for example, a hydrocarbon, an alcohol, a vinyl group-containing cyclic siloxane, or the like can also be used.

The platinum compound may be added in an amount sufficient to promote the addition reaction between the vinyl group-containing organopolysiloxane and the organohydrogenpolysiloxane, and is usually 0.1 to 10 in terms of platinum metal. It is preferably 100 ppm.

The silicone rubber composition was put to practical use.
In addition to the above-mentioned components, the range that does not impair the curing
In the box, various additives can be blended as needed.
You. For example, methylphenyl silicone as a lubricant
SiO to enhance the strength of oil and cured products_Twounit,
(CH_Two= CH) R '_TwoSiO_0.5And R '_TwoSiO
_0.5Unit (where R'does not contain an aliphatic unsaturated bond)
It is a monovalent hydrocarbon group. ) Resin structure
Ganopolysiloxane (Japanese Patent Publication No. 38-36771, Japanese Patent Publication)
(See Japanese Laid-Open Patent Publication No. 45-9476), etc.
However, even if these are included, they are still included in the composition.
Silicon for one vinyl group bonded to all silicon atoms
It is necessary to have 1 to 5 hydrogen atoms bonded to elementary atoms
is there.

In addition, the thermal contraction of the silicone rubber during curing is reduced, the thermal expansion coefficient of the elastic body obtained by curing is reduced,
A filler may be added for the purpose of improving thermal stability, weather resistance, chemical resistance, flame retardancy, mechanical strength, etc., and reducing gas permeability. Examples of such fillers include fumed silica; quartz powder; glass fiber; carbon black; metal compounds such as alumina, iron oxide, and titanium oxide; metal carbonates such as calcium carbonate and magnesium carbonate. Suitable pigments, if necessary,
It is also possible to add dyes, antioxidants and the like. The filler is usually 100 parts by weight of organopolysiloxane,
5 to 200 parts by weight are blended.

The polybutylene terephthalate resin composition of the present invention comprises a two-pack addition-curable silicone rubber (a mixture of a vinyl group-containing organopolysiloxane and a platinum catalyst,
The organohydrogenpolysiloxane is packaged separately, and these are mixed at the time of use), and good adhesion is possible with the prepared one.

[0045]

EXAMPLES The present invention will be specifically described below with reference to examples.

In the examples, "parts" means "parts by weight". The intrinsic viscosity [η] of the polymer is 3 in orthochlorophenol.
It is a value calculated from the solution viscosity measured at 5 ° C.

The terminal carboxyl group concentration (COO
H) is the method of A. Conix {(Makromol. Chem, Vol-26, 22.
6 (1958)} per 10 ⁶ g of polymer.

Examples 1 to 3 and Comparative Examples 1 to 6 Polybutylene terephthalate (intrinsic viscosity: 0.90) using tetrabutoxide titanate 130 was used as a polymerization catalyst.
After drying at ℃ × 5 hours, as a silicon-containing compound, methyl hydrogen silicone oil (manufactured by Toray Dow: product name S
H1107), pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] as a phenol-based antioxidant, and tetrakis [methylene-3--] as a thioether-based antioxidant.
(Dodecylthio) propionate] was uniformly mixed in a V-blender at various ratios shown in Table 1. The obtained mixture was melt-kneaded at a barrel temperature of 250 ° C. using a 44 mm-diameter twin-screw extruder, and the thread discharged from the die was cooled and cut to obtain molding pellets.

Next, after drying the pellets at 130 ° C. for 5 hours, a test piece mold for physical properties was attached to a 5 ounce injection molding machine, the cylinder temperature was 260 ° C., and the mold temperature was 4 °.
Tensile test pieces (AS) under the molding conditions of 0 ° C., injection pressure 700 kg / cm ² , cooling time 20 seconds, and total cycle 35 seconds.
TM4) and an adhesion test piece were molded. The hydrolysis resistance test was carried out by measuring the tensile strength and the elongation at break of a test piece which had been subjected to a wet heat treatment for 60 hours under the conditions of 122 ° C. and a relative humidity of 100%. The heat resistance test was performed by measuring the tensile strength and the elongation at break of a test piece which was heat-treated for 500 hours at a temperature of 170 ° C.

Preparation of addition type silicone rubber: 100 parts by weight of dimethylpolysiloxane (viscosity at 25 ° C .: 1000 cSt) having two methylvinylsiloxane units in one molecule and terminated with a dimethylvinylsiloxy group. 4.6 parts by weight of methyl hydrmediene polysiloxane having 0.739 mol of hydrogen atoms bonded to silicon atoms per 100 g, and 0.12 parts by weight of an octyl alcohol modified solution of chloroplatinic acid (platinum content: 0.5%). It was made.

The adhesion test between the polybutylene terephthalate resin composition and the addition-curable silicone rubber is shown in FIG.
25 mm × length 15 mm × thickness 0.2 mm is applied to the adhesion test piece shown in FIG. 1 and heated at 130 ° C. for 1 minute to cure, and the adhesive strength between the polybutylene terephthalate resin composition and the silicone rubber, and the silicone rubber and the chromium. The peelability between the plated adhesion test piece and a metal jig having the same size was evaluated.

[0052]

[Table 1]

As shown in Table 1, the polybutylene terephthalate resin having a terminal carboxyl group concentration of 35 equivalents / ton is inferior in hydrolysis resistance as shown by the results of PCT, while the terminal carboxyl group concentration is 10 equivalents / 10 ^6. It can be seen that g of polybutylene terephthalate resin gives good results.

Further, the heat aging property is greatly improved by combining a phenol type antioxidant and a thioether type antioxidant.

Further, when a polybutylene terephthalate resin composition is blended with methylhydrogen silicone oil, a desirable result is obtained in which the polybutylene terephthalate molded product and the silicone rubber are firmly adhered and the metal is easily peeled off. It has become possible.

[Example 4, Comparative Examples 7 to 8] In the same manner as in Example 1, the same evaluation was performed on the compositions having the blending ratios shown in Table 2.

As a result, it was found that when a polybutylene terephthalate resin using a tin compound as a catalyst and a phosphorus-based antioxidant were added, the effect of the silicone rubber did not proceed and the product could not be used. The results are shown in Table 2.

[0058]

[Table 2]

[Brief description of the drawings]

FIG. 1 is an elevational view showing a state in which a silicone rubber is sandwiched between two molded products made of the polybutylene terephthalate resin composition of the present invention or a metal, and the two molded products are bonded together.

FIG. 2 is a top (plan) view of the state of FIG.

[Explanation of symbols]

Reference numeral 10 indicates a portion where the surfaces of the two molded products are in contact. 12 is a molded product of polybutylene terephthalate resin. 14
Indicates a metal molded product. Reference numeral 20 is a silicone rubber interposed in the contacting portion.

Claims (1)

[Claims] 1. (A) 100 parts by weight of polybutylene terephthalate having a terminal carboxyl concentration of 15 equivalents / 10 ⁶ g or less and containing a titanium compound as a polymerization catalyst residue,
(B) 0.05 to 3 parts by weight of a silicon compound and / or a polymer thereof having a hydrogen atom directly bonded to at least one silicon atom in one molecule, (C) a phenolic antioxidant 0.01 to A polybutylene terephthalate resin composition having excellent adhesiveness to silicone rubber, which is obtained by blending 0.5 part by weight and 0.01 to 0.5 part by weight of (D) thioether antioxidant.