JP3645750B2 - Polybutylene terephthalate resin molded article excellent in adhesiveness with silicone rubber and method for producing the same - Google Patents

Description

【００４１】
［実施例２及び比較例４、５］
表２に示すＰＢＴ、珪素含有化合物及び／又はその重合体、フェノール系抗酸化剤、チオエーテル系抗酸化剤、及びその他充填材を所定量配合し、金型温度を表２に示すように変えた以外は実施例１と同一の条件で成形体を得、同条件でシリコーンゴムとの接着性を評価した。比較例５については、得られた成形体を１３０℃で２時間アニールした後接着試験に供した。
本発明の樹脂成形体は、良好なシリコーンゴム接着性を示すと共に耐加水分解性が大幅に改善された。
【００４２】
【表２】

【００４３】
本発明によれば、ポリブチレンテレフタレート樹脂の耐加水分解性を大幅に改良し、且つ該ポリブチレンテレフタレート樹脂とシリコーンゴムとが互いに十分実用に耐えうる接着力を以って接着したポリブチレンテレフタレート樹脂成形体とシリコーンゴムとの一体成形体を得ること、及びかかる一体成形体を得るために確実且つ容易に、しかも短時間でポリブチレンテレフタレート樹脂とシリコーンゴムが必要十分な接着再現性を持って接着することを可能とする成形体の製造方法を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polybutylene terephthalate resin molded article having excellent hydrolysis resistance and firmly adhering to silicone rubber with good reproducibility and a method for producing the same.
[0002]
[Prior art]
Thermoplastic polyester resins, especially polybutylene terephthalate resins, are excellent in chemical resistance, heat resistance and mechanical properties, and are widely used as industrial resins. In recent years, with increasing demands for hydrolysis resistance and heat aging resistance, it firmly adheres to silicone rubber that satisfies the above required characteristics in the electric / electronic field and automobile field, and is excellent in heat resistance, electrical characteristics, and weather resistance. There is a need for polybutylene terephthalate resins.
[0003]
Conventionally, as a method of adhering addition-curable silicone rubber and thermoplastic polyester resin, for example, a method of applying a primer on the surface of a molded article and then coating and curing an uncured silicone rubber material on the surface, or self-adhesive silicone A method is known in which a rubber material is coated and cured from above a molded product.
[0004]
JP-B-2-34311 discloses a method of adding an organopolysiloxane containing 30% mol or more of hydrogen atoms directly bonded to silicon atoms to an organic resin and bonding it to an addition-curing type silicone rubber. No. 63-45292 discloses a method in which a silicone rubber is bonded and integrated with an olefin resin grafted with a compound having an aliphatic unsaturated group and a silicon atom-bonded hydrolyzable group, and JP-A-6-171021 discloses a polycarbonate, In JP-A-6-171022 and JP-A-6-171023, polycarbonate, polypropylene and silicone rubber are bonded to polypropylene by adding a compound containing an unsaturated group and a hydrogen atom directly bonded to a silicon atom. An integration method has been proposed.
[0005]
Further, JP-A-9-165516 proposes a method of integrating a thermoplastic resin containing a thermoplastic resin containing a 30% molar aliphatic unsaturated group and a silicone rubber. Further, as previously filed by the present inventors, a compound containing a hydrogen atom directly bonded to a silicon atom was arranged on PBT polymerized with a titanium-based catalyst at a terminal carboxyl group of 15 equivalents / ton or less. Proposes an integral molded body with silicone rubber.
[0006]
[Problems to be solved by the invention]
However, even when a polybutylene terephthalate resin, which is a crystalline resin, is blended with a compound containing a hydrogen atom directly bonded to a silicon atom as an adhesion-imparting component, the adhesive strength may not be satisfied depending on the production conditions of the molded body. There was a problem of improving the adhesion reproducibility.
[0007]
The present invention greatly improves the hydrolysis resistance, which has been increasingly demanded as an industrial resin material for polybutylene terephthalate resin, and has an adhesive strength sufficient to allow the polybutylene terephthalate resin and silicone rubber to withstand practical use. A polybutylene terephthalate resin molding and a silicone rubber bonded together, and a polybutylene terephthalate resin and a silicone rubber are necessary and sufficient to obtain such an integral molding reliably and easily in a short time. It is an object of the present invention to provide an integrated molded body by injection molding or the like, which enables bonding with excellent adhesion reproducibility.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve such problems, the present inventors have found that when the degree of crystallinity of the polybutylene terephthalate on the surface of the bonded part of the resin molding is below a specific level, the storage conditions of the resin molding and the silicone It has been found that it can be reliably and easily bonded in a short time regardless of the rubber application and curing conditions, and has reached the present invention. In particular, it has been found that an integral molded body in which the polybutylene terephthalate resin molded body and the silicone rubber are securely and firmly bonded can be obtained by injection molding.
[0009]
That is, the present invention is based on (A) 100 parts by weight of polybutylene terephthalate obtained by using a titanium compound as a polymerization catalyst and having a terminal carboxyl group concentration of 15 equivalent / ton or less ,
(B) 0.01 to 3 parts by weight of a silicon-containing compound having a hydrogen atom directly bonded to at least one silicon atom in one molecule and / or a polymer thereof;
A molded article comprising to become a resin composition blended, polybutylene terephthalate resin molded article having excellent adhesion to silicone rubber and satisfies the following formula (1).
[0010]
[Equation 3 ]
_{A 917 / A 1578 <1.} 2 (1)
(Wherein A _917, A _1578, respectively 917cm ^-1 adhesive portion surface of the resin molded article, the absorbance at 1578 cm ^-1.)
[0011]
Hereinafter, the present invention will be described in detail.
The polybutylene terephthalate which is the component (A) of the present invention is obtained using a titanium compound as a polymerization catalyst. Since polybutylene terephthalate (A) is obtained using a titanium compound as a polymerization catalyst, it does not inhibit the curing reaction of silicone rubber. Preferred titanium compounds include alkoxide titanate, and tetrabutoside titanate and tetraisopropoxide titanate are particularly preferred. The polybutylene terephthalate which is the component (A) of the present invention needs to have a terminal carboxyl group concentration of 15 equivalents / ton or less. When the terminal carboxyl group concentration exceeds 15 equivalents / ton, no significant improvement in hydrolysis resistance, which is one of the main effects of the present invention, is observed.
[0012]
The polybutylene terephthalate resin which is the component (A) of the present invention is a polyester having terephthalic acid as the main acid component and 1,4-butanediol as the main glycol component. Here, “main” refers to 80 mol% or more, preferably 90 mol% or more, based on the total acid component or total glycol component.
[0013]
Examples of copolymerizable acid components include aromatic dicarboxylic acids other than terephthalic acid, such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ketone dicarboxylic acid, diphenyl sulfone dicarboxylic acid, and the like. And aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexane dicarboxylic acid, tetralin dicarboxylic acid and decalin dicarboxylic acid.
[0014]
Examples of copolymerizable glycol components other than butanediol include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, xylylene glycol, and bisphenol A.
[0015]
In addition, a polyfunctional compound such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid and the like may be copolymerized as long as the polyester does not substantially impair the moldability.
[0016]
The polybutylene terephthalate resin used in the present invention has an intrinsic viscosity (calculated based on a measured value in orthochlorophenol at 35 ° C.) of 0.3 or more, preferably 0.5 or more. preferable. If the intrinsic viscosity is lower than this, the strength is low and it cannot be used.
[0017]
Several reports have been made on the spectral changes associated with crystallization of polybutylene terephthalate resin. Journal of Applied Polymer Science, Vol. 21, 3445-3456 (1977) describes the spectral changes associated with stretching and aging. Analysis has been carried out and it has been reported that the infrared absorption at 1575 cm ⁻¹ originates from vibration of the aromatic ring and does not change with annealing. Polymer, Vol. 18, April, 327-335 (1977) can explain the spectral change by the conformational change of the molecular chain, and the infrared absorption at 917 cm ^-1 is attributed to the CH transverse vibration of the Goushu-trans-Gou chain It is reported that the strength is increased by annealing. Absorption at 917 cm ^-1 increases with crystallization, while the absorption at 1578 cm ^-1 does not change, so it can be considered as an internal standard, and the absorbance ratio A ₉₁₇ / A ₁₅₇₈ is a polycrystal present on the adhesive surface. It can be considered as a measure of the relative crystallization of the butylene terephthalate resin. Here, A _917, A ₁₅₇₈ is the surface of the adhesive portion of each molded article was measured by ATR method infrared spectroscopy shows the absorbance at the maximum wavenumber of the absorption peak near 917cm ^-1 and 1578 cm ^-1. To the silicone rubber polybutylene terephthalate resin molded body is adhered with a bond strength that can withstand sufficiently practical is derived from polybutylene terephthalate adhered portion surface of the resin molded article, the absorbance at 917cm ^-1 and 1578 cm ^-1 The ratio A ₉₁₇ / A ₁₅₇₈ is less than 1.5, preferably 1.2 or less.
[0018]
From the viewpoint of the adhesive strength between the polybutylene terephthalate resin molding and the silicone rubber, the smaller the absorbance ratio A ₉₁₇ / A ₁₅₇₈ is, the more preferable, but the polybutylene terephthalate resin is rapidly crystallized, and can be molded under rapid cooling conditions. A suitable absorbance ratio A ₉₁₇ / A ₁₅₇₈ can be obtained. By molding under practical quenching conditions, the range of absorbance ratio is preferably 0.2 or more, and more preferably 0.5 or more, so that good adhesive strength can be obtained.
[0019]
The silicon-containing compound of component (B) and / or a polymer thereof preferably used in the present invention has at least one hydrogen atom bonded directly to a silicon atom in one molecule. The molecular structure is not particularly limited, and any structure such as linear, branched or cyclic can be used. The viscosity of the silicon-containing compound and / or polymer thereof at 25 ° C. is usually 0.5 to 1000 cSt, and preferably 1 to 200 cSt. If the viscosity is lower than this, it tends to bleed out to the surface of the resin molded product, and if it is higher than this, the adhesiveness is inferior, which is not preferable.
[0020]
As the silicon-containing compound (B) and / or polymer thereof, for example, compounds represented by the following average composition formula are preferably used.
[0021]
[Chemical 1]
H _a (R ¹ ) _b SiO _{(4-ab) / 2}
(In the formula, a and b are numbers satisfying 1 ≦ a ≦ 3, 0 ≦ b ≦ 2 and 1 ≦ a + b ≦ 3. R ¹ is a substituted or unsubstituted one not containing an aliphatic unsaturated bond. Valent hydrocarbon group)
[0022]
In the above average composition formula, R ¹ is usually a group having 1 to 10 carbon atoms, preferably a group having 1 to 6 carbon atoms. Specific examples of R ¹ include alkyl groups such as methyl, ethyl, propyl, and butyl; aryl groups such as phenyl, tolyl, xylyl, and benzyl; cycloalkyl groups such as cyclohexyl; Examples thereof include a chloromethyl group, a cyanoethyl group, 3,3,3, and a trifluoropropyl group in which part or all of the hydrogen atoms of these groups are substituted with a substituent such as a halogen atom or a cyano group. A plurality of R ¹ may be the same or different.
[0023]
The silicon-containing compound of component (B) and / or a polymer thereof can be produced by a method known per se, and usually R ¹ SiHCl ₂ , R ¹ ₃ SiCl, R ¹ ₂ SiCl ₂ , R ¹ ₂ SiHCl. (Wherein, R ¹ is as described above) or by equilibrating the siloxane obtained by hydrolysis in this manner.
[0024]
The compounding amount of the silicon-containing compound (B) and / or polymer thereof used in the present invention is 0.01 to 3 parts by weight, preferably 0.01 to 2 parts by weight per 100 parts by weight of the polybutylene terephthalate resin. It is. If it is less than 0.01 part by weight, the effect of improving the adhesiveness is not seen, and if it exceeds 3 parts by weight, it becomes difficult to release from the mold, and there arises a problem that it adheres to the mating member when assembled as a product.
[0025]
The (C) phenolic antioxidant preferably used in the present invention is a hindered phenol compound and derivatives thereof. Preferred phenolic antioxidants include 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis (4-methyl-6-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, particularly preferably pentaerythrityl tetrakis [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate]. These phenolic antioxidants can be used alone or in combination of two or more.
[0026]
The blending amount of the (C) phenolic antioxidant used in the present invention is required to be 0.01 to 0.5 parts by weight per 100 parts by weight of the polybutylene terephthalate resin, and is 0.1 to 0.00. 3 parts by weight is preferred. When the amount is less than 0.01 part by weight, the effect of improving the heat resistance is small, and even when the amount is more than 0.5 part by weight, the effect of improving the heat aging resistance cannot be expected.
[0027]
In the present invention, the adhesion reproducibility means that a practically sufficient adhesive force is expressed regardless of the storage state of the test piece and the application / curing conditions of the silicone rubber.
[0028]
It is preferable to mix | blend the thioether type | system | group antioxidant which is (D) component with the resin composition of this invention. When the thioether antioxidant (D) is blended, the thioether antioxidant (D) is preferably ditridecyl 3,3′-thiodipropionate, tetrakis [methylene-3- (dodecylthio) propionate], bis [2-Methyl-4- {3-n-alkyl (C12 or C14) thiopropionyloxy} -5-t-butylphenyl] sulfide.
[0029]
When the thioether-based antioxidant is blended, the blending amount is 0 to 0.05 parts by weight, preferably 0.001 to 0.05 parts by weight, per 100 parts by weight of the polybutylene terephthalate resin. If it is added in an amount of more than 0.05 parts by weight, the adhesive strength is lowered when the polybutylene terephthalate resin molded product is stored for a long time and then bonded to silicone rubber.
[0030]
In the resin composition of the present invention, a fibrous reinforcing material such as glass fiber and carbon fiber, an inorganic filler such as granular, amorphous, plate-like, flake-like, etc., as long as the object of the present invention is not impaired. Additives such as nucleating agents, lubricants, antioxidants, UV absorbers, light stabilizers, heat stabilizers, antistatic agents, pigments, and other modifiers such as flame retardants, impact modifiers, fluidity improvers, etc. Can be included.
[0031]
A known method may be employed for the method for producing the resin composition of the present invention. For example, after uniformly mixing using a blender or the like, various methods such as a method of melt kneading at a temperature of 240 to 260 ° C., preferably 250 ° C. using a Banbury mixer, a heating roll, a single screw or a multi screw extruder, etc. Can be manufactured.
[0032]
Under high temperature conditions and long residence time, polybutylene terephthalate deteriorates and mechanical strength and hydrolysis resistance decrease, or a hydrogen atom directly bonded to a silicon atom reacts with the decomposition product of polybutylene terephthalate. Since it is consumed and adhesive strength falls, it is not preferable. In particular, the residence time varies depending on the heating roll or single-screw or multi-screw extruder used, but generally it is preferable to melt and knead under high discharge and high rotation conditions. However, care must be taken because increasing the number of rotations increases the heat generated by shearing.
[0033]
In producing a polybutylene terephthalate resin molded article excellent in adhesiveness with the silicone rubber of the present invention, for example, in injection molding, by molding at a relatively low temperature such as a mold temperature of 40 ° C. or lower, A ₉₁₇ A polybutylene terephthalate resin molding satisfying / A ₁₅₇₈ <1.5 can be obtained. When manufacturing a resin molding, you may shape | mold using the resin composition directly blended without melt-kneading, without using the pellet obtained by the method mentioned above. Also during molding, high temperature conditions and a long residence time are not preferable for the same reason.
[0034]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
In the examples, “parts” means “parts by weight”. The intrinsic viscosity [η] of the polymer is a value calculated from the solution viscosity measured at 25 ° C. in orthochlorophenol. The terminal carboxyl group concentration (COOH) is the number of equivalents per 10 ⁶ g of polymer measured by the method of A. Conix {(Makromol. Chem, 26, 226 (1958)}.
[0035]
The measurement of the absorbance of the infrared absorption of the polybutylene terephthalate resin molding is
apparatus;
BIO-RAD / FTS65A / FT-IR / ST Japan / IR-Plan Micro ATR
ATR crystal; ZnSe
Resolution: 4cm ^-1
Number of integrations: 64 times.
[0036]
[Reference example]
Preparation of addition type silicone rubber 100 parts by weight of methylpolysiloxane (viscosity at 25 ° C .: 1000 cSt) when there are two methylvinylsiloxane units in one molecule and the terminal is terminated with a dimethylvinylsiloxy group, 4.6 parts by weight of methylhydrogenpolysiloxane having 0.739 moles of directly bonded hydrogen atoms per 100 g, and 0.12 parts by weight of octyl alcohol-modified solution of chloroplatinic acid (platinum content: 0.5%) Was added to prepare an addition type silicone rubber.
[0037]
[Example 1及 beauty Comparative Examples 1 and 2, 3]
A predetermined amount of polybutylene terephthalate (hereinafter abbreviated as PBT), silicon-containing compound and / or polymer thereof, phenolic antioxidant, thioether antioxidant, and other fillers shown in Table 1 are blended and mixed uniformly. did. The obtained mixture was melt-kneaded with a 44 mmφ twin screw extruder at a barrel temperature of 250 ° C., and the threads discharged from the die were cooled and cut to obtain molding pellets. The pellets were then dried at 130 ° C. for 5 hours and then subjected to a tensile test (ASTM 4 tension) at a cylinder temperature of 260 ° C., a predetermined mold temperature, and an injection pressure of 700 kg / cm ^{2 using} a 5 ounce injection molding machine. Specimen) was molded. For Comparative Example 2, the obtained molded body was annealed at 130 ° C. for 2 hours and then subjected to an adhesion test.
[0038]
Adhesiveness with silicone rubber is an addition-type silicone rubber prepared by laying a molded body on the lower mold heated to 120 ° C., masking it with a Teflon sheet leaving a 25 mm wide x 15 mm long part, and adjusting it in a reference example. Was applied. The upper mold was then clamped and cured under pressure at 120 ° C. for 10 minutes. The molded body and the cured silicone rubber were pulled in the 180 ° direction and evaluated for peel strength.
[0039]
The hydrolysis resistance test was carried out by measuring the tensile strength of a molded article that had been subjected to a wet heat treatment for 60 hours under the conditions of 122 ° C. and humidity of 100% RH.
[0040]
[Table 1]

[0041]
[Example 2及 beauty Comparative Examples 4 and 5]
Predetermined amounts of PBT, silicon-containing compound and / or polymer thereof, phenolic antioxidant, thioether antioxidant, and other fillers shown in Table 2 were mixed, and the mold temperature was changed as shown in Table 2. Except for the above, a molded product was obtained under the same conditions as in Example 1, and the adhesiveness with silicone rubber was evaluated under the same conditions. For Comparative Example 5 , the obtained molded body was annealed at 130 ° C. for 2 hours and then subjected to an adhesion test.
The resin molded product of the present invention showed good silicone rubber adhesion and greatly improved hydrolysis resistance.
[0042]
[Table 2]

[0043]
According to the present invention, the polybutylene terephthalate resin in which the hydrolysis resistance of the polybutylene terephthalate resin is greatly improved and the polybutylene terephthalate resin and the silicone rubber are bonded with an adhesive force that can sufficiently withstand practical use. To obtain an integrally molded body of a molded body and silicone rubber, and to securely and easily bond such polybutylene terephthalate resin and silicone rubber in a short time in order to obtain such an integrally molded body. The manufacturing method of the molded object which enables it to do can be provided.

Claims (3)

(A) per 100 parts by weight of polybutylene terephthalate obtained using a titanium compound as a polymerization catalyst and having a terminal carboxyl group concentration of 15 equivalents / ton or less ,
(B) 0.01 to 3 parts by weight of a silicon-containing compound having a hydrogen atom directly bonded to at least one silicon atom in one molecule and / or a polymer thereof;
A molded article comprising the resin composition obtained by blending a polybutylene terephthalate resin molded article having excellent adhesion to silicone rubber and satisfies the following formula (1).
[Expression 1]
_{A 917 / A 1578 <1.} 2 (1)
(Wherein A _917, A _1578, respectively 917cm ^-1 adhesive portion surface of the resin molded article, the absorbance at 1578 cm ^-1.) The resin composition further
( C) 0.01 to 0.5 parts by weight of a phenolic antioxidant,
(D) The content of the thioether-based antioxidant is 0 to 0.05 parts by weight of the total weight of the composition,
A polybutylene terephthalate resin molded article excellent in adhesiveness to the silicone rubber according to claim 1, which is a resin composition obtained by blending. An integrated molded body obtained by bonding the molded body according to claim 1 or 2 and silicone rubber .