JPS61266450A - Rigid vinyl chloride resin molding - Google Patents

Abstract

PURPOSE:To provide the titled molding having improved cuttability, by blending an inorg. filler with a rigid vinyl chloride resin in a specified ratio. CONSTITUTION:15-50pts.wt. inorg. filler is blended with 100pts.wt. rigid vinyl chloride resin. By this blending, the molding of said resin becomes harder and brittle. Thus, the molding little exhibits toughness during cutting, so that cuttability is greatly improved and burrs are prevented from being formed. Accordingly, accuracy in cutting is improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in hard vinyl chloride resin molded articles.

(Prior art) Industrial hard vinyl chloride resin plates, etc., used as raw material plates in the manufacture of chemical-resistant equipment, semiconductor devices, etc. that require chemical resistance and precision, have been known to have poor physical properties, especially impact resistance. From the perspective of preventing deterioration, inorganic fillers such as calcium carbonate (hereinafter referred to as charcoal) are rarely blended, and even if they are blended for the purpose of improving moldability, it is said to be no more than 5% by weight. There is. However, hard vinyl chloride resin molded bodies such as hard vinyl chloride resin plates that do not contain such inorganic fillers have the following problems.

(Problems to be Solved by the Invention) In other words, such a hard vinyl chloride resin molded product exhibits so-called "stickiness" during cutting, which increases friction with the cutting machine, making it difficult to cut. Moreover, there were problems such as "paris" occurring and impairing accuracy and appearance.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the machinability of hard vinyl chloride resin molded bodies.

(Means for Solving the Problems) To this end, the gist of the present invention is to incorporate an inorganic filler in an amount of 15 to 50 parts by weight per 100 parts by weight of hard vinyl chloride resin. be.

As a hard vinyl chloride resin, the average degree of polymerization is 700 to 1.
A material having a diameter of about 30'0 is suitable, and it is possible to use not only a material that does not incorporate a plasticizer but also a material that contains a small amount of plasticizer.

On the other hand, as the inorganic filler, powder particles of carbonate, talc, clay, silicate, aluminum hydroxide, etc. are used, and these are mixed into the hard vinyl chloride resin either singly or in combination of two or more. As mentioned above, the blending ratio of this inorganic filler is 15 to 50 parts by weight per 100 parts by weight of the hard vinyl chloride resin.
It is necessary to keep the content within the range of parts by weight. When mixed in such a proportion, chemical resistance etc. will not be significantly reduced, and as seen in the physical property test results in the examples below,
The flexural modulus of the hard vinyl chloride resin molded product increases, and the Charpy impact strength slightly decreases. In other words, the hard vinyl chloride resin molded product becomes hard and brittle. Therefore, as evidenced by the cutting test results in the Examples below, "stickiness" hardly occurs when cutting the hard vinyl chloride resin molded body, the machinability is greatly improved, and the occurrence of "burr" is reduced. This prevents this problem and improves cutting accuracy.

If the blending ratio of the inorganic filler is less than 15 parts by weight, the above-mentioned effect of reducing "stickiness" will not be sufficiently exerted, making it difficult to expect improvement in machinability; If the proportion exceeds 50 parts by weight, there is too much filler, and the physical properties, particularly impact strength, will drop significantly, making the material unsuitable for industrial use.In either case, the object of the present invention can be satisfactorily achieved. It becomes impossible to do so.

As seen in the results of the cutting test and physical property test described below, the effect of mixing inorganic fillers as described above is remarkable when the blending ratio of the filler is around 4 parts per 25 mm. It is particularly noticeable when these are mixed in a weight ratio of 10:5 to 10:20. The reason for this is not clear, but perhaps the lubricity of talc blends well with the brittleness of charcoal, resulting in "
It is presumed that this is to further improve the anti-stickiness effect.

Also, when an inorganic filler with a particle size of about 3 to 9 microns is selected and used, the above effect becomes remarkable when mixed with the vinyl chloride resin.

In addition to the above-mentioned inorganic filler, the hard vinyl chloride resin molded article of the present invention also contains conventional heat stabilizers such as tribasic lead sulfate, dibutyltin malate, and mercapto, and calcium stearate. It goes without saying that suitable amounts of lubricants such as , higher fatty acid esters, pigments such as titanium oxide, carbon blank, etc. are blended.

(Example) Next, the present invention will be explained with reference to Examples.

Five types of hard vinyl chloride resin plate-shaped molded bodies (thickness 1 Qmm) A and B having the composition ratios shown in Table 1 below.

C, D, and E were produced by extrusion molding, and a cutting test was conducted using an NC router.

For comparison, a hard vinyl chloride resin plate (thickness 10 mm) F without inorganic filler and a Bakelite plate (thickness lQ) were used.
A cutting test was also conducted for G (mm) in the same manner.

These results are shown in Table 1 below. The presence or absence of "paris" was determined by the naked eye, and the machinability was comprehensively evaluated by a skilled worker who conducted the test.

Furthermore, a hard vinyl chloride resin plate-shaped molded article C according to the present invention,
A physical property test was conducted on hard vinyl chloride resin board F containing no inorganic filling agent and E, and the results are shown in Table 2 below.

(Hereinafter, blank space) As is clear from the above test results (Table 1), the hard vinyl chloride resin plate-shaped molded products A-E of the present invention have better machinability than F, which does not contain an inorganic filler. is good and "Paris"
In particular, the molded body C of the present invention has excellent machinability and is comparable to Bakelite plate G. Also, this molded body C
As is clear from Table 2, the flexural modulus is considerably increased compared to hard vinyl chloride resin sheet F without inorganic fillers, but the Charpy impact strength is decreased, making it hard and brittle. It can be seen that there is no significant difference in other physical properties. In addition, regarding the physical properties of the molded product E, the Charpy impact strength is reduced to about 1/2 compared to that of the molded product F, and if it is less than this, various problems will occur as an industrial plate and it cannot be used.

(Functions and Effects) As can be understood from the above explanation, the hard vinyl chloride resin molded article of the present invention, in which 15 to 50 parts by weight of an inorganic filler is mixed with 100 parts by weight of hard vinyl chloride resin, Due to the "stickiness" suppressing effect of the inorganic filler, the impact resistance strength etc. will not be significantly reduced (the machinability will be greatly improved, the occurrence of "burr" will be eliminated, and the machining accuracy will be greatly improved). Therefore, the hard vinyl chloride resin molded article of the present invention can be used in chemical-resistant equipment, semiconductor equipment, developing machines, etc. that require processing accuracy, impact resistance, chemical resistance, etc.
It is suitable for use as an industrial material for various etching devices in place of conventionally used Bakelite, etc., and does not have the drawbacks of increased mff1 and dimensional changes due to water absorption, etc., which are seen in Bakelite. Therefore, it can be said to be extremely desirable.

Claims (1)

[Claims] (1) A hard vinyl chloride resin molded article, characterized in that 15 to 50 parts by weight of an inorganic filler is mixed with 100 parts by weight of hard vinyl chloride resin.