JPH0688310B2 - Method for producing thermoplastic resin extruded plate having matte surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a thermoplastic resin extruded plate having low gloss and good design.

(Prior Art) A thermoplastic resin extruded plate is used for a wide range of applications because of its excellent weather resistance and processability. And, with the expansion of its applications, various characteristics have come to be required, and there is a demand for an extruded plate having a low surface gloss, that is, a so-called loose matte state, and recently, further. In addition to having a matte state, it is also required to have a design property in its surface properties.

As a method for producing a matte extruded plate, (1) a method of blending a thermoplastic resin with a matting agent, kneading and extruding.

(2) A method of forming fine irregularities on the surface of the thermoplastic resin with an embossing roll.

Etc. can be mentioned.

(Problems to be Solved by the Invention) The above method (1) is a method in which inorganic powders such as calcium carbonate and talc are blended and kneaded and extruded. It was not always easy to manufacture a board. That is, if the blending ratio of the inorganic powder is increased to reduce the glossiness, it is not always easy to disperse the inorganic powder in the thermoplastic resin, and the blending ratio is sufficient to obtain a matte surface having a sufficiently low glossiness. , Agglomerates of the compound appeared on the surface of the plate, fish-eye-like defects were generated, and a beautiful matte surface could not be obtained.

The method of shaping with the embossing roll of (2) is vacuum forming,
There is a defect that a so-called loose luster phenomenon occurs in which fine irregularities on the surface are smoothed by a molding process such as blow molding, and the glossiness of the surface of the molded product is increased. Recently, there has been a demand for diversification of the surface properties of matte plates. Therefore, a wide range of products from extruded plates with low gloss to extruded plates with a mirror surface are continuously manufactured without interrupting production. A method is needed. However, in the embossing roll method, it is not possible to shape matte plates with different surface properties with the same roll, so various rolls are required for each brand, equipment costs increase, and operation interruptions are required to replace rolls. , Not economical.

(Means for Solving Problems) The inventors of the present invention have made earnest studies in view of the above-mentioned circumstances, and blended a mica pulverized body with a thermoplastic resin and kneaded and extruded the mixture to prevent aggregation and low gloss. The present invention has been completed by finding that it is possible to manufacture a matt plate having a ground glass tone.

That is, the present invention is a method of extruding a thermoplastic resin in a molten state to continuously obtain a flat plate, in which a molten resin strip containing finely powdered mica is extruded into a first roll adjusted to have a desired thickness. The method for producing a thermoplastic resin extruded plate having a matte surface is characterized in that after passing between the first roll and the second roll, cooling is performed without being pressed between the subsequent rolls.

The thermoplastic resin as used in the present invention has a usual meaning and is not particularly limited. Acrylic resin, polycarbonate resin, preferably used among them,
Mention may be made of vinyl chloride resins, MS resins and polystyrene resins. These may be used alone or in combination of two or more. The thermoplastic resin may contain a dye, a pigment, a lubricant, and an ultraviolet absorber depending on the purpose of use,
For example, a modifier such as an impact resistance agent may be included.

The mica used in the present invention may be either synthetic mica or natural mica. Mixing amount of mica is 10
It is 1 to 20 parts by weight with respect to 0 parts by weight, and the preferable blending amount is 5 to 15 parts by weight. When the amount of mica is less than 1 part by weight, the glossiness of the surface of the obtained matte plate becomes high, and a good matte surface cannot be obtained. When the amount of mica compounded exceeds 20 parts by weight, the glossiness and surface property of the surface are hardly improved even if mica is further added. Then, a matte plate having an arbitrary glossiness and surface property can be obtained by adjusting the amount of mica compounded.

The mica used in the present invention needs to be in the form of fine powder. The average particle size of the particles is preferably 3 to 100 μm as measured by the gravity sedimentation method. If the average particle size is less than 3 μ, the matting effect is small, and if the average particle size is more than 100 μ, the surface property is poor.
Further, when the average particle diameters are the same, those having a narrow particle size distribution width are preferable because they give a beautiful matte surface.

In the present invention, cooling without pressurizing between the rolls means cooling without forcibly applying pressure during the cooling process, and for example, adjusting the desired thickness between the first roll and the second roll. After that, cooling is performed on the endless belt, or the gap between the second roll and the third roll is set sufficiently larger than the plate thickness.

(Effect) According to the method of the present invention, it is possible to easily obtain a beautiful matte extruded plate having a low gloss.

Further, the method of the present invention is different from the shaping method using a roll,
It is possible to manufacture continuously with normal equipment, and its value is industrially great.

(Example) Hereinafter, the present invention will be described with reference to an example.

Examples 1 to 8 and Comparative Examples 1 to 8 100 parts by weight of methyl methacrylate copolymer beads containing 6% of methyl acrylate and having a molecular weight of 160,000, and having an average particle diameter of 5 μm measured by gravity sedimentation method, muscovite (muscovite).
After mixing in a predetermined amount and stirring and mixing with a Henschel mixer
Using a 120 mmφ vent type single screw extruder, extrude into a flat plate shape with a T-shaped die with a width of 1100 mm at a resin temperature of 260 ° C., and cool it with a three-roll roll as shown in FIG. 1 to obtain a flat plate with a plate thickness of 2 mm. It was At this time, the second roll and the third
The roll gap was 10 mm, and no pressure was applied between the second roll and the third roll. For comparison, a flat plate was manufactured by pressurizing the linear pressure between the second roll and the third roll so as to be 35 kg / cm. The 60 ° specular gloss of the surfaces of these flat plates was measured according to JIS Z 8741 (Glossiness measurement method).
The results are shown in Table 1.

Examples 5-8, Comparative Examples 5-8 Example 1 except that finely powdered mica having an average particle size of 50 [mu] was used.
4 and Comparative Examples 1 to 4 were used to manufacture matte plates.
The evaluation results are shown in Table 2.

Example 9 A matte plate was produced and evaluated in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 4 except that polycarbonate having a molecular weight of 25,000 was used as the thermoplastic resin. The results are shown in Table 3.

Comparative Examples 13 to 17 Table 4 shows examples in which a predetermined amount of talc having an average particle diameter of 4.2 μ was blended as a matting agent and an example in which a predetermined amount of calcium carbonate having an average particle diameter of 3.8 μ was blended as a matting agent.

In Comparative Examples 13 and 14, the glossiness was high and a matte surface was not formed, and the talc fine powder aggregated with the surface of the resin plate, remarkably impairing its appearance. In Comparative Examples 15 to 17, fine aggregation does not occur,
It had a high gloss and did not have a matte surface.

[Brief description of drawings]

 FIG. 1 is a conceptual diagram for carrying out the present invention.

Front page continuation (72) Inventor Tokutaro Dote 4-7 Kyowa-machi, Nakajo-machi, Kitakanbara-gun, Niigata Kyowa Gas Chemical Industry Co., Ltd. Nakajo Plant (56) References JP-A-60-184559 (JP, A)

Claims (2)

[Claims] 1. A method of continuously extruding a molten thermoplastic resin to obtain a flat plate, wherein a first molten resin band containing extruded fine powder mica is adjusted to a gap to give a desired plate thickness. A method for producing a thermoplastic resin extruded plate having a matte surface, characterized in that after passing between a roll and a second roll, cooling is performed without being pressed between successive rolls. 2. A thermoplastic resin having a finely powdered mica content of 100.
Claims 1 to 20 parts by weight with respect to parts by weight
Item 6. A method for producing a thermoplastic resin extruded plate having a matte surface according to item.