JP4090848B2 - Method for providing metallic-tone crystalline resin molded product - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for providing a metallic-tone resin molded article. More specifically, the present invention relates to a method for providing a metallic resin molded product having excellent texture and excellent strength, rigidity, and chemical resistance.
[0002]
[Prior art]
Metallic resin molded products are lighter than metal parts, and have been used for electrical and electronic parts, automobile parts, building material furniture parts, industrial parts, and the like as materials replacing metal.
Examples of metallic-like non-crystalline resin molded products include examples using ABS resin, AS resin, polystyrene resin, polycarbonate resin, acrylic resin and non-crystalline polypropylene resin (for example, Patent Documents 1 and 2, 3). Certainly, in the case of an amorphous resin, although it has an excellent metallic texture, it is difficult to have chemical resistance as an inherent property of the resin, its resistance to solvents and detergents is small, and its application range is limited. Further, there are some cases where strength, rigidity, etc. are required in various uses, but for example, the reinforcing effect with glass fiber or the like is small and there is a limit in this point of view.
[0003]
Examples of metallic resin crystalline resin molded products include polyethylene resin, polypropylene resin, polyamide resin, and polyester resin (see, for example, Patent Documents 1 and 4). In the case of a crystalline resin, although chemical resistance, strength, and rigidity are excellent, the depth of metallic color tone is poor and it is not at a level that can withstand practical use widely. For this reason, for example, it is necessary to apply clear coating or the like to the surface of the molded product, which is complicated, and the metallic texture is still not satisfactory.
[0004]
On the other hand, from the viewpoint of the processing method, there is an example in which a device is devised (for example, see Patent Document 5). In this example, a crystalline resin such as a polyamide resin or a polyethylene terephthalate resin is specifically shown. However, although the metallic texture is improved, the metallic material composition is small (for example, less than 10% by weight). However, the texture is not satisfactory. Further, the mold structure is also complicated, and is not suitable for a molded product having a complicated shape.
[0005]
[Patent Document 1]
JP-A-5-93091 [Patent Document 2]
Japanese Patent Laid-Open No. 10-182873 [Patent Document 3]
JP 2002-113740 A [Patent Document 4]
JP 2002-69220 A [Patent Document 5]
JP-A-9-174562 [0006]
[Problems to be solved by the invention]
In view of such a situation, it is an object of the present invention to provide a metallic resin molded product that is excellent in metallic color tone and excellent in strength, rigidity, and chemical resistance.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor has used a mold in which the temperature of the mixture of the crystalline thermoplastic polyester resin and the metallic pigment is adjusted to be lower than the glass transition temperature Tg of the crystalline thermoplastic polyester. After the injection molding, the molded product that has been heat-treated at a temperature equal to or higher than the cold crystallization temperature Tcc of the component (A) has been found to have excellent metallic color texture and excellent chemical resistance, strength, and rigidity. Invented.
[0008]
That is, the present invention relates to the following inventions.
[ 1 ] A mixture of (A) 100 parts by weight of a crystalline thermoplastic polyester resin and (B) 0.01 to 10.0 parts by weight of a metallic pigment has a mold temperature lower than the glass transition temperature Tg of the component (A). A method in which injection molding is performed using an adjusted mold, and a molded product after injection molding is heat-treated at a temperature equal to or higher than the cold crystallization temperature Tcc of the component (A) .
[2] further contains a (C) inorganic filler, a mixture of component (C) is the component (A) and (C) 70% by weight or less based on the total weight of the components, the method according to [1].
[ 3 ] The component (C) is at least one selected from talc, mica, wollastonite, kaolin, calcium carbonate, barium sulfate, carbon fiber, potassium titanate whisker, glass fiber, glass beads, and glass flakes. The method according to [2] above.
[0009]
[ 4 ] The component (C) is selected from one or more selected from talc, mica, wollastonite, kaolin, calcium carbonate, barium sulfate, carbon fiber and potassium titanate whisker, and glass fiber, glass beads and glass flakes. The method according to [2] above, which is a combined use with one or more kinds of glass materials.
[ 5 ] The method according to any one of [1] to [4], wherein a part of the mold is adjusted to a glass transition temperature Tg or higher of the component (A) during injection molding.
[ 6 ] The method according to any one of [1] to [ 5 ], wherein the component (A) is a polytrimethylene terephthalate resin.
[0010]
The present invention is described in detail below.
The (A) crystalline thermoplastic polyester resin in the present invention is a polyester resin mainly using terephthalic acid as an acid component and mainly using ethylene glycol, trimethylene glycol, or tetramethylene glycol as a glycol component. Examples of such resins include polyethylene terephthalate resin (hereinafter sometimes abbreviated as PET), polytrimethylene terephthalate resin (hereinafter sometimes abbreviated as PTT), and polybutylene terephthalate resin (hereinafter abbreviated as PBT). And the like. Among these, polyethylene terephthalate resin and polytrimethylene terephthalate resin, which have a relatively low crystallization rate in a practical processing temperature region, are preferable, and polytrimethylene terephthalate resin is more preferable.
[0011]
In the (A) crystalline thermoplastic polyester resin of the present invention, a mixture of two or more of PET, PTT and PBT described above and an alloy are also preferably used. Furthermore, it may be a mixture or alloy with another polyester resin as long as the characteristics are not impaired.
Further, within the range not impairing the effects of the present invention, (A) the crystalline thermoplastic polyester resin includes polycarbonate resins, olefin resins such as polyethylene and polypropylene, polystyrene, rubber-reinforced polystyrene, acrylonitrile-styrene copolymer, ABS. One or more thermoplastic resins such as styrene resins such as resins, polyacetals, polyamides, modified polyphenylene oxide, polyphenylene sulfide, and polymethyl methacrylate may be blended.
[0012]
Hereinafter, the polytrimethylene terephthalate resin preferably used as the crystalline thermoplastic polyester resin (A) in the present invention will be described in detail as an example.
The polytrimethylene terephthalate resin in the present invention is a polyester resin mainly using terephthalic acid for the acid component and mainly trimethylene glycol for the glycol component.
Examples of other acid components other than terephthalic acid include aromatic dicarboxylic acids other than terephthalic acid, such as phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylmethane. Dicarboxylic acid, diphenyl ketone dicarboxylic acid, diphenyl sulfone dicarboxylic acid and the like; succinic acid, adipic acid, sebacic acid and other aliphatic dicarboxylic acids; cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids; ε-oxycaproic acid, hydroxybenzoic acid, Examples include oxydicarboxylic acids such as hydroxyethoxybenzoic acid. In addition, it is preferable that a terephthalic acid is 80 mol% or more of an acid component.
[0013]
The trimethylene glycol is selected from 1,3-propanediol, 1,2-propanediol, 1,1-propanediol, 2,2-propanediol, or a mixture thereof. , 3-propanediol is particularly preferred and is preferably at least 80 mol% of the glycol component.
Examples of other glycol components include ethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, neopentyl glycol, cyclohexanedimethanol, xylylene glycol, diethylene glycol, polyoxyalkylene glycol, and hydroquinone. .
[0014]
In addition, the polyester described above includes a branched component, for example, trifunctional or tetrafunctional ester-forming acid such as tricarballylic acid, trimesic acid, trimellitic acid, or trifunctional such as glycerin, trimethylolpropane, pentaerythritol, etc. Alternatively, a tetrafunctional ester-forming alcohol may be copolymerized, in which case the amount of the branched component is 1.0 mol% or less, preferably 0.5 mol% or less of the total dicarboxylic acid component, Preferably, it is 0.3 mol% or less. Further, PTT may be used in combination of two or more of these copolymer components.
[0015]
The method for producing PTT used in the present invention is not particularly limited, but is described in, for example, JP-A Nos. 51-140992, 5-262862, and 8-311177. Terephthalic acid or an ester-forming derivative thereof (for example, a lower alkyl ester such as dimethyl ester or monomethyl ester) and trimethylene glycol or an ester-forming derivative thereof are heated at a suitable temperature and time in the presence of a catalyst. Examples thereof include a method in which the resulting glycol ester of terephthalic acid is subjected to a polycondensation reaction to a desired degree of polymerization at a suitable temperature and time in the presence of a catalyst.
[0016]
The PTT of the present invention preferably has a number average molecular weight of 5,000 to 100,000, and Mw / Mn showing a molecular weight distribution is preferably 1.5 to 4.5. Furthermore, it is preferable that 1 to 20% of molecules having a molecular weight of 100,000 or more are contained.
The number average molecular weight and molecular weight distribution can be measured by, for example, an osmotic pressure method, a terminal quantification method, or a GPC method (gel permeation chromatography). Specifically, HLC-8120 manufactured by Tosoh Corporation as a measuring device, Showa Denko HFIP804-803 (two 30 cm columns) as a column, hexafluoroisopropanol (hereinafter referred to as HFIP) as a carrier, a standard sample Can be carried out at a temperature of 40 ° C. and a flow rate of 0.5 ml / min using PMMA manufactured by Polymer Laboratory.
[0017]
Examples of the (B) metallic pigment used in the present invention include aluminum, colored aluminum, nickel, tin, copper, gold, silver, platinum, iron oxide, stainless steel, titanium, and other metal particles, mica pearl pigment, color graphite, and color glass. Examples thereof include fibers and colored glass flakes. Of these, pearl pigments made of aluminum, nickel, tin, and mica are more preferable. These pigments may be used alone or in combination of two or more.
The average particle diameter of the metallic pigment is preferably 1 to 500 μm, more preferably 5 to 300 μm in terms of number average particle diameter. When the number average particle diameter is 1 to 500 μm, the surface smoothness is excellent and the metallic color tone is vividly expressed.
[0018]
(B) The compounding quantity of a metallic pigment is 0.01-10.0 weight part with respect to 100 weight part of (A) crystalline thermoplastic polyester resin, More preferably, 100 weight part of crystalline thermoplastic polyester resin It is 0.05-8.0 weight part with respect to this. If the blending amount is 0.01 to 10.0 parts by weight with respect to 100 parts by weight of the crystalline thermoplastic polyester resin, a clear color tone is expressed without deteriorating the mechanical properties inherent to the crystalline thermoplastic polyester resin. Can be made.
[0019]
The mixture of (A) crystalline thermoplastic polyester resin and (B) metallic pigment referred to in the present invention is, for example, a composition obtained by melting and kneading component (B) in component (A) using a known extruder or the like. Alternatively, a master batch (hereinafter sometimes abbreviated as MB) obtained by melting and kneading component (B) in a high concentration in a thermoplastic resin and a blend of component (A), and further, component (A) It refers to a blend with component (B). In the above, the thermoplastic resin used for MB is preferably the same as the component (A) used, but other (A) component or a known thermoplastic resin other than the component (A) is used. It doesn't matter.
[0020]
In the injection molding of the present invention, a conventionally known injection molding method is preferably used. A hollow injection molding method can also be preferably used.
The glass transition temperature Tg as used in the present invention refers to a resin sample 10-20 mg heated from room temperature to 280 ° C. at a heating rate of 100 ° C./min using a differential scanning calorimeter, and held for 2 minutes. When the sample is rapidly cooled to 0 ° C. at a set temperature decrease rate of 500 ° C./min, held at 0 ° C. for 1 minute, and then heated to 280 ° C. at a temperature increase rate of 20 ° C./min, Refers to the top temperature.
In injection molding in the present invention, it is important that the mold temperature is adjusted to be lower than the glass transition temperature Tg of the component (A). When the mixture of component (A) and component (B) is melted and injected into the mold in an injection molding machine, the surface of the molded product is rapidly cooled, and component (A) is solidified in a non-crystalline state. Form. Therefore, the surface of the molded product shows a metallic tone with a texture.
[0021]
In the present invention, a part of the mold may be adjusted to the glass transition temperature Tg or higher of the component (A). For example, when the design surface of the molded product exists only on the fixed side of the mold, only the fixed side of the mold is adjusted to be lower than the glass transition temperature Tg of the component (A), and the moving side of the mold is set to (A) You may adjust to the glass transition temperature Tg or more of a component.
In the present invention, the molded article after injection molding is heat-treated at a temperature equal to or higher than the cold crystallization temperature Tcc of the component (A) . This ensures that crystallization progresses chemical resistance of the molded article surface, but improves various properties such as heat resistance, metallic texture of the surface is maintained good.
The temperature for the heat treatment is not less than the cold crystallization temperature Tcc, but the upper limit is preferably less than the cold crystallization temperature Tcc + 100 ° C. Further, it is more preferably a cold crystallization temperature Tcc or more and a cold crystallization temperature Tcc + less than 70 ° C. However, it goes without saying that it is less than the melting point of the component (A) in order to maintain the shape of the molded product.
[0022]
The cold crystallization temperature Tcc as used in the present invention refers to a resin sample of 10 to 20 mg heated from room temperature to 280 ° C. at a heating rate of 100 ° C./min and held for 2 minutes using a differential scanning calorimeter. , Rapidly cooled to 0 ° C. at a set temperature drop rate of 500 ° C./min, held at 0 ° C. for 1 minute, and then heated to 280 ° C. at a temperature increase rate of 20 ° C./min. Refers to temperature.
Moreover, in this invention, it is preferable to mix (C) inorganic filler with the crystalline thermoplastic polyester resin which comprises it according to the performance required for the target molded article.
[0023]
The (C) inorganic filler referred to in the present invention is an inorganic filler that is generally known for crystalline thermoplastic polyester resins.
(C) Inorganic fillers preferred in the present invention include talc, mica, wollastonite, kaolin, barium sulfate, calcium carbonate, carbon fiber, potassium titanate whisker, glass fiber, glass beads and glass flakes. Other inorganic fillers include asbestos fibers, silica fibers, silica / alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, and metals such as stainless steel, aluminum, titanium, copper, and brass. Examples include fibrous materials.
[0024]
In addition, the powder particles include silica, quartz powder, calcium silicate, aluminum silicate, clay, silicate such as diatomaceous earth, metal oxide such as iron oxide, titanium oxide, zinc oxide, and alumina, magnesium carbonate. Examples thereof include metal carbonates such as calcium sulfate, metal sulfates such as calcium sulfate, silicon carbide, silicon nitride, and various metal powders.
These inorganic fillers may be used alone or in combination of two or more. In particular, one or more selected from talc, mica, wollastonite, kaolin, barium sulfate, calcium carbonate, carbon fiber and potassium titanate whisker, and one or more glass materials selected from glass fiber, glass beads and glass flakes Is preferably used together.
[0025]
The content of the inorganic filler is preferably 70% by weight or less based on the total weight of the crystalline thermoplastic resin and the inorganic filler, from the viewpoint of the surface appearance of the molded body. When two or more kinds of inorganic fillers are used in combination, the total weight of the inorganic filler is preferably 70% by weight or less based on the total weight of the crystalline thermoplastic resin and the inorganic filler.
In the present invention, a colorant can be added to the crystalline thermoplastic resin constituting it according to the performance required for the intended molded article.
[0026]
Colorants used in the present invention are conventionally known pigments, dyes, etc. for crystalline thermoplastic polyester resins, and preferred pigments include organic pigments such as monoazo and condensed azo, anthraquinone, and isoindolinone. , Heterocyclic, perinone, quinacridone, perylene, thioindigo, dioxazine and the like. Examples of the inorganic pigment include carbon black, titanium oxide, titanium yellow, iron oxide, ultramarine blue, cobalt blue, a fired pigment, and a metallic pigment.
Examples of organic dyes include anthraquinone, heterocyclic and perine dyes.
[0027]
In the crystalline thermoplastic polyester resin of the present invention, conventionally known additives such as an antioxidant, a thermal stabilizer, a release agent, a lubricant, a weathering agent, etc. are added to the crystalline thermoplastic polyester resin as desired. You may mix | blend.
In the metallic-tone crystalline resin molded product of the present invention, it is also preferable to apply a coating such as clear to the surface of the molded product, if necessary.
The metallic-tone crystalline resin molded product of the present invention is not only excellent in the texture of metallic color tone, but also excellent in chemical resistance, strength, rigidity, heat resistance, etc., and automobiles such as foil caps and engine covers. It is suitably used for parts, interior / exterior covers of electrical and electronic parts, building material furniture parts such as crescents, and the like.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited at all by these examples.
First, the crystalline thermoplastic polyester resin, metallic pigment, talc, glass fiber, and measurement conditions in the examples are described.
(1) Crystalline thermoplastic polyester resin intrinsic viscosity [η] is 1.02, and the number average molecular weight is 9800, Mw / Mn = 2.5, and the proportion of molecular weight of 100,000 or more is 5.8. % Polytrimethylene terephthalate resin It should be noted that the intrinsic viscosity [η] is a value determined by the following defining formula.
[Η] = lim1 / C × (η _r −1) [C → 0]
Η _r in the formula is a value obtained by dividing the viscosity at 35 ° C. of a diluted solution obtained by dissolving a polyester resin in o-chlorophenol having a purity of 98% or more by the viscosity of the solvent at the same temperature, and is defined as a relative viscosity. It is what has been. C is the weight (g) of the solute in 100 ml of the diluted solution.
[0029]
(2) Metallic pigment Aluminum pigment having an average particle diameter of 40 μm (Metax S; manufactured by Toyo Aluminum Co., Ltd.)
(3) Talc Microace L-1 (Nippon Talc Co., Ltd.)
(4) A chopped strand having a glass fiber diameter of 10 μm and a length of 3 mm, which is surface-treated with a mixture of an aminosilane coupling agent and an epoxy sizing agent.
(5) Glass transition temperature Tg and cold crystallization temperature Tcc
Using a differential scanning calorimeter DSC7 manufactured by PerkinElmer, about 12 mg of a sample was heated from room temperature to 280 ° C. at a heating rate of 100 ° C./min, held at that temperature for 2 minutes, and then set to 500 ° C./min. The sample was rapidly cooled to 0 ° C. at a temperature lowering rate, held at 0 ° C. for 1 minute, and then heated to 280 ° C. at a temperature rising rate of 20 ° C. At this time, the top temperature (Tg) of the endothermic peak that appears first and the top temperature (Tcc) of the exothermic peak were determined.
When the glass transition temperature Tg and the cold crystallization temperature Tcc of the polytrimethylene terephthalate resin used in this example were measured, the following values were obtained.
Glass transition temperature Tg: 47 ° C
Cold crystallization temperature Tcc: 74 ° C
[0031]
[Example 1]
A polytrimethylene terephthalate resin and 0.5 parts by weight of an aluminum pigment having an average particle diameter of 40 μm as a metallic pigment (100 parts by weight of the polytrimethylene terephthalate resin) are added, and a twin screw extruder (manufactured by Toshiba Machine Co., Ltd. Melt-kneading was performed using TEM35, a biaxial same-direction screw rotation type, L / D = 47.6 (D = 37 mmφ). At this time, the screw rotation speed was 300 rpm, the cylinder temperature was 260 ° C., and the extrusion rate was 60 kg / Hr. The polymer was discharged in a strand form from the tip nozzle, and water-cooled and cut to obtain pellets. The pellets were dried in a nitrogen atmosphere at 120 ° C. for 5 hours, and then a 100 mm × 100 mm × 3 mmt flat plate was formed by injection molding. Molding was performed using a 100-ton molding machine, and the resin temperature was 250 ° C. and the mold temperature was 30 ° C. on both the fixed side and the moving side.
When the surface of the flat molded product was observed, it was a metallic color tone excellent in a deep texture.
Further, the flat plate was heat-treated at 100 ° C. for 1 hour and then observed on the surface, but there was no change in the metallic color tone.
[0032]
[Example 2]
80% by weight of polytrimethylene terephthalate resin and 20% by weight of talc are mixed, and 1.0 part by weight of an aluminum pigment having an average particle diameter of 40 μm is added as a metallic pigment (100 parts by weight of polytrimethylene terephthalate resin). Except that, pellets were obtained in the same manner as in Example 1.
Using the pellets, the flat plate used in Example 1 was molded by injection molding. For molding, a 100t molding machine was used, and the resin temperature was 250 ° C, the mold temperature was 30 ° C on the fixed side, and 95 ° C on the moving side.
When the surface of the flat molded product was observed, the surface on the fixed side had a metallic color tone excellent in deep texture.
Further, the flat plate was heat-treated at 100 ° C. for 1 hour and then observed on the surface, but there was no change in the metallic color tone of the fixed side surface.
[0033]
[Example 3]
65% by weight of polytrimethylene terephthalate resin, 10% by weight of talc and 25% by weight of glass fiber were mixed, and 1.2 parts by weight of aluminum pigment having an average particle diameter of 40 μm as a metallic pigment (100% by weight of polytrimethylene terephthalate resin) The pellets were obtained by performing the same operation as in Example 1 except that the part was added.
Using the pellets, the flat plate used in Example 1 was molded by injection molding. For molding, a 100t molding machine was used, and the resin temperature was 250 ° C, the mold temperature was 30 ° C on the fixed side, and 95 ° C on the moving side.
When the surface of the flat molded product was observed, the surface on the fixed side had a metallic color tone excellent in deep texture.
Further, the flat plate was heat-treated at 100 ° C. for 1 hour and then observed on the surface, but there was no change in the metallic color tone of the fixed side surface.
[0034]
[Comparative Example 1]
Using the pellets prepared in Example 1, the same operation as in Example 1 was performed except that the mold temperature was set to 95 ° C. on both the fixed side and the moving side to obtain a flat plate.
When the surface of the flat molded product was observed, the entire surface was gray and not a deep metallic color.
[0035]
[Comparative Example 2]
The same procedure as in Example 2 was performed to obtain a flat plate, except that the pellets prepared in Example 2 were used and the mold temperature was 95 ° C. on both the fixed side and the moving side.
When the surface of the flat molded product was observed, the entire surface was gray and not a deep metallic color.
[0036]
【The invention's effect】
As is clear from the examples and comparative examples, the metallic tone crystalline resin molded product according to the present invention is excellent in metallic color tone with excellent deep texture, automobile parts, electrical and electronic parts, building material furniture parts, industrial parts. It is used suitably for etc.

Claims (6)

(A) A mixture of 100 parts by weight of a crystalline thermoplastic polyester resin and 0.01 to 10.0 parts by weight of a (B) metallic pigment is adjusted so that the mold temperature is less than the glass transition temperature Tg of the component (A). A method in which injection molding is performed using a mold, and the molded product after injection molding is heat-treated at a temperature equal to or higher than the cold crystallization temperature Tcc of the component (A) . The method according to claim 1, further comprising (C) an inorganic filler, wherein the component (C) is a mixture of 70% by weight or less based on the total weight of the component (A) and the component (C). The component (C) is at least one selected from talc, mica, wollastonite, kaolin, calcium carbonate, barium sulfate, carbon fiber, potassium titanate whisker, glass fiber, glass beads and glass flakes. The method according to claim 2. The component (C) is one or more selected from talc, mica, wollastonite, kaolin, calcium carbonate, barium sulfate, carbon fiber and potassium titanate whisker, and one or more selected from glass fiber, glass beads and glass flakes. The method according to claim 2, wherein the glass material is used in combination. The method according to any one of claims 1 to 4, wherein a part of the mold is adjusted to a glass transition temperature Tg or higher of the component (A) during injection molding. (A) component, the method according to any one of claims 1 to 5, characterized in that the polytrimethylene terephthalate resin.