JP2678937B2 - Thermoplastic polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermoplastic polymer composition having excellent coatability, which comprises a thermoplastic polymer and a compound having two or more specific functional groups, and a method for producing the same. Regarding This composition has an excellent coating property without substantially impairing the mechanical properties of the thermoplastic polymer as the main component.

INDUSTRIAL APPLICABILITY The thermoplastic polymer composition of the present invention is preferably used in the field of machine parts, automobile parts, electric / electronic parts and the like, particularly for parts requiring coating.

[Problems to be Solved by Conventional Techniques and Inventions] Since thermoplastic polymers are excellent in productivity, they are used in large quantities in the fields of machine parts, automobile parts, electric parts, etc. as molded products. However, although these parts are often used after being coated, ordinary thermoplastic polymers are inferior in coatability, and therefore improvement in coatability has been demanded.

Many proposals have been made for improving the paintability of thermoplastic polymers. For example, (1) a method of treating the surface of a molded article with a solvent or plasma, (2) a method of mixing a thermoplastic polymer with an inorganic reinforcing material, a filler, etc., (3) a thermoplastic polymer with good coatability. A method of blending with a compound or copolymerization is known.

The method (1) has the drawbacks that the treatment is complicated and the productivity is poor, and the method (2) has a high melt viscosity of the mixed composition, resulting in poor moldability, and molding with an inorganic material. There are drawbacks such as poor surface smoothness.
The method (3) discloses a method of blending a polymer such as rubber having good paintability and high polarity (JP-A-51-145553 and JP-A-57-85837).
However, it is well known that when different kinds of polymers are melt-blended, it is difficult to mix them uniformly, and properties such as mechanical strength and flexibility of the obtained polymer blend are significantly lowered. Therefore, this method has a problem in practical use even though the coating property is improved. Also,
When a low-molecular weight compound is blended, the low-molecular weight compound bleeds onto the surface of the molded article during coating, making good coating difficult, which is a disadvantage.

[Means for Solving the Problems] An object of the present invention is to provide a thermoplastic polymer composition having good coatability and substantially smooth surface of a molded article without substantially impairing mechanical strength. is there.

As a result of intensive studies, the present inventors have found that the object of the present invention can be achieved by a thermoplastic polymer composition comprising a thermoplastic polymer and two or more specific compounds that react with each other to form a polymer when heated. .

That is, the present invention relates to (A) a thermoplastic polymer composed of polystyrene and / or polypropylene (B) a polyether polyol, a polyester polyol, a polycarbonate diol, a polybutadiene diol, a polyoxyalkylene polyamine, a dimer diamine and a butadiene having an amino group. A compound having at least two active hydrogen groups consisting of at least one component selected from the group consisting of acrylonitrile copolymers (C) consisting of a compound having two or more isocyanate groups, wherein (A) is 40 to 98 parts by weight. , (B) + (C) is 60
˜2 parts by weight, and (B) with an active hydrogen group and (C)
It can be achieved by a thermoplastic polymer composition obtained by heating a mixture having an equivalent ratio with the isocyanate group of 0.5 to 2 at a temperature of 60 ° C. or higher.

In the present invention, the compounds (B) and (C) have a low molecular weight, and unlike the case of blending polymers, it is easy to uniformly disperse (B) and (C) in (A). is there. Also, a mixture of (A), (B) and (C) is added to 60
When heated to a temperature of ℃ or more, the compounds of (B) and (C) react with each other in the state of being uniformly dispersed in (A), resulting in a polymer having good coatability.

Since the thermoplastic polymer composition comprising (A), (B), and (C) has each component uniformly dispersed, the thermoplastic polymer of (A) is coated with almost no loss of mechanical strength. And the smoothness of the surface of the molded product are good.

The thermoplastic polymer of the present invention comprises polystyrene and / or
Alternatively, it is polypropylene or a copolymer of these polymers.

Examples of the compound having two or more active hydrogen groups used in the present invention include polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxypropylated glycerin and polytetramethylene glycol, polyester polyols such as polycaprolactone diol, Polycarbonate diol, polybutadiene diol, poly tail (manufactured by Mitsubishi Kasei Co., Ltd.), polyoxyalkylene polyamines such as polyoxypropylene diamine, dimer diamine, butadiene acrylonitrile copolymer having an amino group (manufactured by Ube Industries, Ltd.,
Hycar AT polymer etc.), etc. These compounds can be used alone or in combination.

Examples of the compound having two or more isocyanate groups used in the present invention include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, polyphenylmethylene polyisocyanate and carbodiimide group. Diphenylmethane-4,4'-diisocyanate, toluidine diisocyanate, xylene diisocyanate, isophorone diisocyanate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 1,6-hexamethylene diisocyanate,
1,10-decamethylene diisocyanate, cumene-2,4-
There are diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, naphthalene diisocyanate, anthracene diisocyanate, 2,4,6-toluene isocyanate, and dimers and trimers of the above isocyanates. These can be used alone or as a mixture. It is also possible to use block type isocyanates obtained by reacting these isocyanates with caprolactam or phenol.

The thermoplastic polymer composition of the present invention comprises 40 to 98 parts by weight of the thermoplastic polymer (A), more preferably 60 to 95 parts by weight and (C) a compound having two or more active hydrogen groups. The total amount of the compounds having two or more isocyanate groups is 60 to 2 parts by weight, more preferably 40 to 5 parts by weight, and the active hydrogen group of the compound (B) and the isocyanate group of the compound (C) are And an equivalent ratio thereof is 0.5 to 2, more preferably 0.8 to 1.5.

When the amount of the thermoplastic polymer (A) used is more than the above upper limit, the coating property is hardly improved, and when it is less than the lower limit, practical mechanical properties are largely deteriorated, which is not preferable. When the equivalent ratio of the active hydrogen group to the isocyanate group is at least the above upper limit and at most the above lower limit, unreacted (B) or (C) compounds remain, and these unreacted compounds remain on the surface of the molded article during coating. Bleeds and impairs paintability, which is not preferable.

The production of the thermoplastic polymer composition of the present invention is carried out at a temperature above the melting point of the thermoplastic polymer of (A), (A), (B),
The mixture of (C) can be prepared by a known melt-kneading machine such as an extruder such as a twin-screw kneader, a Banbury mixer, or a kneader. It can also be produced by mixing (A), (B) and (C) in a solvent of the thermoplastic polymer (A) and heating to a temperature of 60 ° C or higher. Also,
It is also possible to use a kneaded product or a mixture of (A) and (B) and (A) and (C). At this time, (B)
Mixing / kneading of the reaction product of (C) and (A) is not preferable. Also, the thermoplastic polymer composition of the present invention can be used as a masterbatch and mixed with (A).

The thermoplastic polymer composition of the present invention can be processed into molded articles, sheets and the like by known melt molding methods such as injection molding methods and extrusion molding methods.

Further, the resin composition of the present invention may be added with various reinforcing materials and fillers within a range that does not impair the moldability and physical properties.

Specific examples of the reinforcing material and filler used in the present invention include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber. , Metal fibers such as stainless steel, aluminum, titanium, copper, brass, magnesium, and organic fibers such as polyamide, fluororesin, polyester, acrylic resin, copper, iron, nickel, zinc, tin, lead, stainless steel, aluminum, Metal powder such as gold and silver, fumed silica, aluminum silicate, glass beads, carbon black, quartz powder, talc, titanium oxide, iron oxide,
Examples include calcium carbonate and diatomaceous earth. As the fibrous substance, those having an average fiber diameter of 5 to 30 μm and a fiber length of 50 μm to 30 mm can be used. As these reinforcing materials and fillers, those surface-treated with a known silane coupling agent or titanate-based coupling agent can also be used.

The amount of the reinforcing material and the filler used is the resin composition 100 of the present invention.
It is 1 to 300 parts by weight, preferably 10 to 250 parts by weight based on parts by weight. These reinforcing materials and fillers can be used alone or in admixture of two or more.

The resin composition of the present invention, as long as the object of the present invention is not impaired, hindered phenol, hydroquinone, thioether, osphites and their antioxidants and heat stabilizers such as copper compounds, resorcinol, UV absorbers such as salicylate, benzotriazole, benzophenone, stearic acid and its salts, mold release agents such as stearyl alcohol, halogen-based, phosphoric ester-based, melamine or cyanuric acid-based flame retardants, flame retardant aids, dodecylbenzene. It is also possible to add one or more additives such as antistatic agents such as sodium sulfonate and polyalkylene glycol, crystallization accelerators, dyes and pigments.

 Hereinafter, the present invention will be described by way of examples.

[Example] Tensile strength, impact strength described in Examples and Comparative Examples,
The method for measuring the adhesion and dispersibility of the paint is as follows.

(1) Tensile strength Measured according to ASTM D638. (Unit: kgf / cm ² ) (2) Impact strength (Izod impact strength with notch) Measured according to ASTM D256. The thickness of the test piece is 1/8
Inches. (Unit: kgf · cm) (3) Adhesion of coating material Measured according to JIS D 0202.

Test piece coating method The test piece was degreased with isopropyl alcohol prior to coating. Then, as a bottom coating material, PLAGROS 1100S (manufactured by NOF CORPORATION) was applied in a film thickness of about 30 μm and left for 10 minutes. This was placed in an oven at 140 ° C. for 30 minutes, taken out after curing, and cooled at room temperature for 30 minutes. next,
Melami No. 1 white as top coating (Nippon Yushi Co., Ltd.)
Applied) to a film thickness of about 30 μm, leave it for 10 minutes, then
Cured in an oven at 140 ° C for 30 minutes. After taking out from the oven, leaving at room temperature for 24 hours or more, and cooling, the adhesiveness of the coating material was measured.

(4) Dispersibility The dispersibility was evaluated from the SEM photograph of the composition. (Unit μ
m) Example 1 5 kg of xylene and 800 g of polypropylene (Ube Polypro J105G, manufactured by Ube Industries, Ltd.) were placed in a container with an internal volume of 10 liter equipped with a heater, a stirrer, and cooling, and the temperature was raised to 140 ° C. to obtain polypropylene. Was dissolved. To this, 175.3 g of polypropylene glycol having a number average molecular weight of 2000 and 24.7 g of xylylene diisocyanate are added, and the mixture is stirred at 140 ° C. with stirring 20
Polypropylene glycol and xylylene diisocyanate were reacted for a minute. This xylene solution was poured into a large amount of methanol to cause polypropylene and polyurethane (a reaction product of polypropylene glycol and xylylene diisocyanate) to break out, and then subjected to rocking. The mixture of the localized polypropylene and polyurethane was further washed with methanol to remove unreacted materials, and then dried.
980 g of a mixture of polypropylene and polyurethane was obtained.
A sample obtained by crushing this mixture was used with a compact injection molding machine with a mold clamping pressure of 30 tons and a cylinder temperature of 250 ° C and a mold temperature of 5
A test piece was prepared by molding at 0 ° C. The tensile strength, impact strength, adhesion to paint and dispersibility of this test piece were measured. Physical properties such as tensile strength were measured using an absolutely dry test piece. The results of tensile strength, impact strength, and adhesion to paint are shown in Table 1. The dispersibility was shown in the figure, but the dispersibility was good and no dispersed particles could be observed.

Comparative Example 1 Polypropylene (Ube Polypro J105G) was used as a test piece under the same molding machine and molding conditions as in Example 1. The results of tensile strength, impact strength and adhesion of dye are shown in Table 1.

Comparative Example 2 Polyurethane was prepared by previously reacting polypropylene glycol having a number average molecular weight of 2000 with xylylene diisocyanate. Next, after dissolving 800 g of polypropylene (Ube Polypro J105G) in 5 kg of xylene at 140 ° C., 180 g of the above-prepared polyurethane was put in this solution and mixed at 140 ° C. for 20 minutes while stirring.

A test piece was prepared in the same manner as in Example 1 except for the above. The results of tensile strength, impact strength and paint adhesion are shown in Table 1. Also, the dispersibility is shown in the figure, but the dispersed particle size was large and the dispersibility was poor.

Example 2 In the same container as in Example 1, 5 kg of toluene and polystyrene (Dencast Styrol GP1, manufactured by Denki Kagaku Kogyo Co., Ltd.) 900 were used.
g was added and the temperature was raised to 80 ° C. to dissolve polystyrene. Polyoxypropylene triol with a number average molecular weight of 3000 (Sannix GP-3000, manufactured by Sanyo Kasei Co., Ltd.)
95.9 g and diphenylmethane-4,4'-diisocyanate 4.
A test piece was prepared in the same manner as in Example 1 except that 1 g was added and reacted. The results of tensile strength, impact strength and paint adhesion are shown in Table 1. The dispersibility was the same as in Example 1.

Comparative Example 3 A test piece of polystyrene (Dencast Styrol GP1) was prepared using the same molding machine and molding conditions as in Example 1. The results of tensile strength, impact strength and paint adhesion are shown in Table 1.

EFFECT OF THE INVENTION A composition comprising a thermoplastic polymer, a compound having two or more active hydrogen groups and a compound having two or more isocyanate groups has substantially the same mechanical properties as the main component thermoplastic polymer. Excellent paintability without loss.

[Brief description of the drawings]

1 and 2 are SEM photographs showing particle shapes of fracture surfaces of the thermoplastic polymer compositions of Example 1 and Comparative Example 2 of the present invention.

Continuation of the front page (56) References JP-A-58-25338 (JP, A) JP-A-58-83039 (JP, A) JP-A-62-1715 (JP, A) JP-A-63-27533 (JP , A) JP-A-63-182328 (JP, A) JP-A-2-163164 (JP, A) JP-A-2-36248 (JP, A)

Claims (1)

(57) [Claims] 1. A thermoplastic polymer comprising (A) polystyrene and / or polypropylene (B) polyether polyols, polyester polyols, polycarbonate diols, polybutadiene diols, polyoxyalkylene polyamines, dimer diamines and butadiene acrylonitrile having amino groups. A compound having two or more active hydrogen groups, which comprises at least one component selected from the group consisting of copolymers (C) a compound having two or more isocyanate groups, and (A) is 40 to 98 parts by weight, (B) + (C) is 60
˜2 parts by weight, and (B) with an active hydrogen group and (C)
A thermoplastic polymer composition obtained by heating a mixture having an equivalent ratio with the isocyanate group of 0.5 to 2 at a temperature of 60 ° C. or higher.