JP2000281882A - Exterior part material made of polybutylene terephthalate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject exterior part material having excellent resistance to hydrolysis property without a gas generation in melting and blending nor peeling off in molding and having excellent water repellent property without losing a gloss even at a high temperature and high humidity by molding a resin composition obtained by blending a polybutylene terephthalate resin with hardened silicone powder. SOLUTION: A resin composition obtained by blending (A) 100 pts.wt. of polybutylene terephthalate resin with (B) 0.1-30 pts.wt. of hardened silicone powder obtained by absorbing a silicone oil, e.g. organopolysiloxane of the formula: R3SiO[R2SiO]nSiR3 [R is a (substituted)monofunctional hydrocarbon or a hydroxyl group; (n) is an integer] and preferably having 0.1-20,000 μm particle diameter is molded. Preferably, the silicone oil is liquid and has 100-200,000 cSt dynamic viscosity at 25 deg.C. The resin material can be added with a filler (e.g. potassium titanate fibers, mica or the like), as necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an external part made of polybutylene terephthalate resin. More specifically, the present invention relates to a molded part having excellent water repellency and appearance obtained by molding a resin composition obtained by adding and mixing a cured silicone powder in which a silicone oil is absorbed into a polybutylene terephthalate resin.

[0002]

2. Description of the Related Art Polybutylene terephthalate resin is a highly crystalline polymer,
It is a material with excellent mechanical properties. However, since it has a polyester structure, it is easily susceptible to hydrolysis, and the decomposition proceeds particularly under high temperature and high humidity, and it has been unsuitable for external parts requiring water repellency. On the other hand, water-repellent liquid substances such as silicone oil are added and blended with the resin and melt-kneaded to impart water repellency and have excellent antifouling properties. It is often used as an excellent appearance part. However, since water-repellent liquid substances such as silicone oil have extremely poor compatibility and affinity with polybutylene terephthalate resin, it is extremely difficult to mix them, and gas generation occurs during kneading. Even when such a composition can be prepared, when the composition is molded, the liquid substance easily seeps onto the resin surface, and its lubricating action causes slippage between the resins or between the resin and the screw. Poor penetration into the machine, poor plasticization, and the like occur, and in severe cases, processing becomes impossible. The present invention has been made in view of the above problems, has no gas generation during melt-kneading, does not show peeling during molding, has excellent hydrolysis resistance, and does not lose gloss even under high temperature and high humidity. It is an object of the present invention to provide an appearance component having excellent water repellency.

[0003]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies. As a result, by using a specific polybutylene terephthalate resin composition material, no gas is generated during melt-kneading and good repellency is obtained. The inventors have found that a molded article having an aqueous surface appearance can be obtained, and have completed the present invention.
That is, the present invention provides (A) a polybutylene terephthalate resin
An external part made of a polybutylene terephthalate resin obtained by molding a resin composition in which 0.1 to 30 parts by weight of (B) a silicone oil-absorbed cured silicone powder is blended with respect to 100 parts by weight.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the components of the resin material used in the present invention will be described in detail. First, (A) polybutylene terephthalate resin, which is a base resin of the resin material used in the present invention, is a polybutylene terephthalate or an ester-forming derivative thereof and a polyalkylene glycol having 4 carbon atoms or an ester-forming derivative thereof obtained by polycondensation. Butylene terephthalate. In addition, polybutylene terephthalate may be a copolymer containing 70% by weight or more per se. As dibasic acid components other than terephthalic acid and its lower alcohol esters, aliphatic and aromatic polybasic acids such as isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and succinic acid or ester-forming derivatives thereof And the like, as a glycol component other than 1,4-butanediol, a normal alkylene glycol such as ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol,
Hexamethylene glycol, neopentyl glycol,
Cyclohexanedimethanol, lower alkylene glycols such as 1,3-octanediol, bisphenol A, aromatic alcohols such as 4,4'-dihydroxybiphenyl, bisphenol A ethylene oxide 2 mol adduct, bisphenol A propylene oxide 3 mol Alkylene oxide adduct alcohols such as adducts,
Examples thereof include polyhydroxy compounds such as glycerin and pentaerythritol, and ester-forming derivatives thereof.
In the present invention, any polybutylene terephthalate produced by polycondensation using the above compound as a monomer component can be used as the component (A) of the present invention, and used alone or as a mixture of two or more. Further, the intrinsic viscosity of the polybutylene terephthalate resin used is not particularly limited, but is 0.3 to 1.5 dl / g at a concentration of 0.5% by weight and 25 ° C. using o-chlorophenol as a solvent.
Are preferred, more preferably 0.55 to 1.2 dl / g, especially 0.55
~ 1.0 dl / g is preferred.

[0005] Next, in the present invention, (B) a cured silicone powder having absorbed silicone oil is added. The cured silicone powder that has absorbed the silicone oil is
(A) By being added to and blended with the polybutylene terephthalate resin, gas generation during melt-kneading is suppressed, silicone oil does not exude during molding, and exfoliation on the molded product surface is eliminated. It has the effect of improving the releasability from the lubrication performance. In addition, since it is water repellent, it has the effect of suppressing the intrusion of moisture from the molded product surface and delaying the hydrolysis of polybutylene terephthalate even under high temperature and high humidity, and the gloss of the molded product surface even under such severe conditions Is maintained, and mechanical properties are also maintained. From the above viewpoints, addition of a cured silicone powder that has absorbed silicone oil is an essential component in the present invention in order to obtain a good molded product. The amount of component (B) added is
0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight per 100 parts by weight
Parts by weight. If the amount is too small, the water repellent effect and the lubricating effect are low, and no effects on good appearance under high temperature and high humidity, hydrolysis resistance, and mold release properties are observed. In the case of excessive, gas generation during kneading, screw biteability during molding, etc.
A molding problem occurs, which is not preferable. The silicone oil absorption-curing silicone powder used here means that the silicone oil is pre-mixed with 0.5 to
It is obtained by mixing 80% by weight, absorbing and powdering by any method. As the silicone forming the silicone oil absorption-curing silicone powder, a conventionally known silicone rubber or silicone gel can be used. As the silicone rubber, an organic peroxide-curable silicone rubber, an addition reaction-curable silicone rubber,
A condensation-curable silicone rubber can be used, but an addition-reaction-curable silicone rubber, particularly an addition-reaction-curable silicone rubber or a condensation-reaction-curable silicone rubber, is preferred because it is easy to produce and easy to handle. Silicone gels are silicones containing organopolysiloxane as a main component and partially forming a three-dimensional network by crosslinking, and exhibiting deformation and limited fluidity by applying stress. The cured silicone powder used in the present invention contains the following silicone oil and has a particle size of 0.1 to 20000 μm, particularly 5 to 300 μm.
It is preferably in the range of μm. When the thickness is less than 0.1 μm, the physical property modification hardening of various materials decreases, and
This is because if it exceeds 3, it becomes difficult to add and blend into various materials. The silicone oil to be absorbed by the cured silicone powder is a liquid organopolysiloxane having a siloxane bond in the main chain, and its type is not particularly limited. For example, it is represented by the general formula R ₃ SiO [R ₂ SiO] _n SiR ₃ (where R is a substituted or unsubstituted monovalent hydrocarbon group or a hydroxyl group, and n is an integer). In the above formula, R is an alkyl group such as a methyl group, an ethyl group or a propyl group; an alkenyl group such as a vinyl group or an allyl group; an aralkyl group such as a cycloalkyl group or a β-phenylethyl group;
It is a substituted or unsubstituted monovalent hydrocarbon group exemplified by 3,3,3-trifluoropropyl group, 3-mercaptopropyl group, 3-aminopropyl group, 3-glycidoxypropyl group and the like.

[0006] The molecular weight of the silicone oil is not particularly limited, but is preferably in a liquid form, particularly at 25 ° C.
Having a kinematic viscosity of 100 to 200,000 cSt is preferred. In particular, it is preferably in the range of 500 to 10,000 cSt.

[0007] The resin material used in the present invention may optionally contain a filler. Such a filler is preferably blended in order to obtain excellent properties such as mechanical strength, heat resistance, dimensional stability, and electrical properties, and is particularly effective for increasing rigidity. For this purpose, a fibrous, powdery or plate-like filler is used depending on the purpose. Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, Examples include fibrous materials of metals such as copper and brass.
In addition, a high melting point organic fibrous substance such as polyamide, fluororesin, and acrylic resin can also be used. Examples of the particulate filler include carbon black, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate,
Silicates such as kaolin, talc, clay, diatomaceous earth, wollastonite, oxides of metals such as iron oxide, titanium oxide and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, calcium sulfate, barium sulfate And other metal powders such as silicon carbide, silicon nitride, silicon nitride, boron nitride, and the like. Examples of the plate-like inorganic filler include mica, glass flake, various metal foils, and the like. The type of the filler is not particularly limited, and one or more fillers may be added, but it is particularly preferable to use potassium titanate fiber, mica, talc, and wollastonite. The filler is desirably added and blended in an amount of preferably 50 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of polybutylene terephthalate. When the filler is added in excess, the moldability is poor and the toughness is reduced.

Further, in the resin composition used in the present invention, a known substance generally added to a thermoplastic resin or the like can be added and used in order to impart desired properties according to the purpose. For example, a stabilizer such as an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, a flame retardant auxiliary, an antistatic agent, a lubricant, a release agent, a coloring agent such as a dye or a pigment, a plasticizer, and the like are mixed. It is possible. In particular, the addition of an antioxidant for improving heat resistance is effective. The cured silicone powder that has absorbed the silicone oil, which is an essential component of the present invention, has lubricity, so that the release agent can be omitted.

The preparation of the polybutylene terephthalate resin composition used in the present invention is easily carried out by equipment and a method generally used as a conventional resin composition preparation method.
For example, (1) a predetermined amount of components constituting the composition of the present invention are mixed at once and melt-kneaded by a single-screw or twin-screw extruder to obtain pellets of a desired composition. (2) With a single-screw or twin-screw extruder having two or more raw material input ports, a resin, a stabilizer, a pigment component, and the like are charged from the first input port and melt-kneaded, and then the second raw material input port is provided. Add more inorganic filler,
Melt-kneading to obtain pellets of the desired composition, and the like.

The method for molding the resin composition of the present invention is not particularly limited, such as injection molding, extrusion molding, blow molding, etc., but injection molding is particularly preferred. The obtained molded product was measured according to JIS Z8741 specular gloss measurement method.
By measuring the glossiness of the smooth surface, it has a 90 ° specular gloss of 90% or more, and even 100% or more. Further under moist heat
Glossiness of 90% or more can be maintained even after 200 hours. In general, even under high temperature and high humidity where the polybutylene terephthalate resin is considered to be degraded and deteriorated to lower the gloss, the method of the present invention does not show a decrease in the gloss. The resulting molded article has water repellency and retains its surface gloss over a long period of time even under high temperature and high humidity. Therefore, kitchen parts, washing machine parts, washing tools, bath / sanitary parts, and peripheral devices thereof It is suitable as an appearance part excellent in water repellency typified by

[0011]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Examples 1 to 8 and Comparative Examples 1 to 12 A polybutylene terephthalate resin having an intrinsic viscosity of 0.82 was mixed with a cured silicone powder having absorbed silicone oil at a ratio shown in Table 1, and then melt-kneaded by a twin-screw extruder. A pellet-shaped composition was prepared. Next, using this pellet, a test piece was prepared by injection molding,
An evaluation was performed. Further, for comparison, as shown in Table 2, evaluation was also made of a silicone oil-free cured silicone powder-free product and a silicone oil and / or cured silicone powder-added product.

The evaluation items and evaluation methods are as follows. Surface Peeling During Molding: Using a screw-type injection molding machine, a flat plate having a thickness of 1 mm was formed at a screw temperature of 250 ° C., and the injection speed was increased to 1, 2, and 4 m / min, and the occurrence of surface peeling was confirmed. If no peeling occurred, it was evaluated as “absent”, and if peeling occurred, it was evaluated as “present”. Water repellency: Using a screw-type injection molding machine, a plate having a thickness of 3 mm was formed at a screw temperature of 250 ° C and a mold temperature of 70 ° C, and the water contact angle was measured. After wiping off the plate surface with ethanol so as not to damage it, measurement was performed at room temperature and 25 ° C. using a contact angle measuring instrument FACE CA-Z manufactured by Kyowa Interface Science Co., Ltd. Surface appearance under heat and humidity resistance; Using a screw-type injection molding machine, mold a plate with a thickness of 3 mm at a screw temperature of 250 ° C and a mold temperature of 70 ° C, and put it in a thermo-hygrostat at 80 ° C and 95% humidity,
The 60 ° specular gloss was measured at predetermined time intervals with a portable gloss meter HG246 manufactured by Suga Test Instruments Co., Ltd.

[0013]

[Table 1]

Silicone oil-containing cured silicone powders 1, 2, 3; kinematic viscosities of 60,000 cSt, 1000 cSt, respectively
A cured silicone powder with an average particle size of about 50 μm, absorbing 60% by weight of 12500 cSt silicone oil.

[0015]

[Table 2]

In Comparative Example 1, surface peeling was not evaluated because no silicone component was added. Comparative Example 10 was not evaluated because molding was impossible due to poor penetration. Silicone oils 1, 2, 3; kinematic viscosity 60,000 cS each
t, 1000cSt, 12,500cSt Cured silicone powder; average particle size about 20μm

[0017]

As described above, the appearance component having excellent water repellency made of the polybutylene terephthalate resin composition of the present invention is obtained by adding and blending a cured silicone powder in which silicone oil has been absorbed into a polybutylene terephthalate resin. After kneading, it is obtained by molding the obtained resin composition, surface peeling does not occur during molding, and good moldability
Has the appearance. A molded article obtained from this resin material is suitably used particularly for an appearance part having excellent water repellency which requires water repellency and appearance.

Claims (7)

[Claims] (1) Polybutylene terephthalate resin (A) 100
An external part made of a polybutylene terephthalate resin obtained by molding a resin composition containing (B) 0.1 to 30 parts by weight of a cured silicone powder in which silicone oil is absorbed with respect to part by weight. 2. The external part according to claim 1, wherein the surface gloss of the molded article having a smooth surface after 200 hours of wet heat treatment is 90% or more in terms of 60 ° specular gloss. 3. The external part according to claim 1, wherein the molded article having a smooth surface has a water contact angle of 85 ° or more. 4. The appearance component according to claim 1, wherein (A) the polybutylene terephthalate resin has an intrinsic viscosity of 0.55 to 1.2. 5. The external part according to claim 1, wherein the silicone oil (B) is liquid at room temperature. 6. A silicone oil having a viscosity of 100 to 200,000 cSt at 25.degree.
The external appearance component according to any one of claims 1 to 5, wherein the external component is powdered by absorbing 80% by weight. (B) The average particle size of the cured silicone powder is (B)
The appearance component according to any one of claims 1 to 6, wherein the thickness is 0.1 to 20000 µm.