JPH11209424A - Chlorinated vinyl chloride resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chlorinated vinyl chloride resin having excellent heat resistance and therformability. SOLUTION: There is provided a chlorinated vinyl chloride resin prepared by chlorinating a vinyl chloride resin and having an average chlorine content of 68-72 wt.% and a melt viscosity (at 200 deg.C) of 8×10<4> to 2×10<4> P. It is desirable that the average-degree of polymerization of the vinyl chloride resin is 400-600, and the chlorinated vinyl chloride resin is desirable for calendering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chlorinated vinyl chloride resin having excellent heat resistance and good thermoformability.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resin (hereinafter referred to as CPV)
C) is generally a vinyl chloride resin (hereinafter referred to as PVC).
Chlorination). CPVC retains flame-retardant and chemical-resistant properties, which are said to be advantages of PVC, and
C is expected to be used in a wide range of applications because it has improved the low heat resistance temperature which is said to be a disadvantage of C. On the other hand, PVC has a major drawback that it cannot be used at temperatures of 60 to 70 ° C. or higher because of its low heat deformation temperature. On the other hand, the heat deformation temperature of CPVC is higher by 20 to 40 ° C. than that of PVC, and the heat resistance, which is a drawback of PVC, is improved.

[0003] However, CPVC has a higher viscosity at the time of melting than PVC, and is difficult to mold. Therefore, C
When molding PVC, it is necessary to melt and mold at a higher temperature than PVC. However, CPVC tends to undergo thermal degradation when heated to a high temperature, and tends to be decomposed and colored. Further, the heat resistance of CPVC increases in proportion to the chlorine content of CPVC, but on the other hand, the melt viscosity increases and molding processing becomes difficult.

[0004] Therefore, in a thermoforming method which involves heating, melting and plasticizing steps such as extrusion molding, injection molding, calender molding, press molding and blow molding, CPVC generally has a chlorine content of less than 68% by weight. Is used. Although CPVC having an average chlorine content of 68% by weight or more has already been developed, it cannot be used for the thermoforming method for the above-mentioned reason, and is mostly limited to uses dissolved in a solvent.

CPV having an average chlorine content of 68% by weight or more
C has high heat resistance, but at the same time, has a high melt viscosity, and thermoforming requires molding at a high temperature of 210 ° C. or higher. However, when thermoforming at a high temperature of 210 ° C. or more, there is a problem in that the molded product is colored, decomposed or burnt. Therefore, when molded at a relatively low temperature of 180 to 200 ° C. as in the case of CPVC having an average chlorine content of less than 68% by weight, although coloring is small and burns are not produced, the gel is molded in a state where it is not sufficiently melted, Insufficiency leads to deterioration of the physical properties of the molded article and deterioration of the appearance of the molded article. For these reasons, the molding temperature of CPVC is limited, and its use range is narrowed.

[0006] Therefore, in order to have a high heat resistance and to obtain a good molded product even when thermoforming at a relatively low temperature,
There has been a need to improve the melt viscosity of CPVC.
As a technique for increasing the heat resistance of CPVC without increasing the average chlorine content so much and without increasing the melt viscosity significantly, a method of adding a heat resistance improver such as a polymaleimide resin or a polystyrene resin is known. I have. However, the heat resistance improver is expensive and needs to be added in a large amount of several tens of percent, resulting in a considerable increase in cost.

As a conventional technique for improving the melt viscosity of CPVC and obtaining good thermoformability, a method of adding a processing aid such as a plasticizer has been generally attempted. Also in this case, there is a problem that the cost is increased by the addition, and the heat resistance temperature of the molded article obtained by the addition is lowered.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has an average chlorine content of 68% by weight.
As described above, a CPVC having excellent heat resistance, low melt viscosity and good thermoformability is provided. That is, an object of the present invention is to provide a CPVC which retains the excellent properties of PVC, reduces the melt viscosity thereof while maintaining the excellent heat resistance of CPVC, and obtains a molded article having good heat resistance. .

[0009]

SUMMARY OF THE INVENTION The present invention relates to a thermoforming CP.
VC is a chlorinated vinyl chloride resin obtained by chlorinating a vinyl chloride resin, and has an average chlorine content of 68 to 7
At 2% by weight, the melt viscosity at 200 ° C. is 8 × 10 ⁴ to
It is characterized by 20 × 10 ⁴ poise.

The average chlorine content of the CPVC used in the present invention is limited to 68-72% by weight. When the average chlorine content is less than 68% by weight, the heat distortion temperature is low, and a molded article having a sufficiently high heat-resistant temperature cannot be obtained. On the other hand, if the average chlorine content exceeds 72% by weight, the melt viscosity of CPVC becomes too high and thermoforming becomes difficult.

The melt viscosity at 200 ° C. of the CPVC used in the present invention is limited to 8 × 10 ^{4 to} 20 × 10 ⁴ poise. When the melt viscosity exceeds 20 × 10 ⁴ poise,
Insufficient kneading during thermoforming causes problems such as deterioration of physical properties and deterioration of appearance. When the molding temperature is increased to 210 ° C. or higher, the melt viscosity decreases, but CPVC is decomposed, and the resulting molded product is colored and burned, which causes problems such as build-up in a molding die and the resulting fuzziness. Occurs.
Conversely, if the melt viscosity is less than 8 × 10 ⁴ poise,
There is a problem that it is difficult to maintain the molding after coming out of the mold, and it is difficult to obtain a good molded body, and it is easy to cause sticking to the mold, which is likely to cause the molded article to be worn out and to build up. .

In the present invention, the average degree of polymerization of PVC is 4
It is preferably from 50 to 600. Average degree of polymerization is 60
If it exceeds 0, a sufficient decrease in melt viscosity does not occur during thermoforming, and a CPVC having a target melt viscosity cannot be obtained when the average chlorine content is in the range of 68 to 72% by weight. In addition, the adhesiveness to the mold during thermoforming is so strong that thermoforming becomes difficult, and the physical properties such as impact resistance of the obtained molded article are significantly reduced, which is not preferable.

The CPVC of the present invention has an average chlorine content of 68.
７２72% by weight, the melt viscosity at 200 ° C. is 8 × 10
^{Since it is 4 to} 20 × 10 ⁴ poise, it is suitably used for extrusion molding, injection molding, blow molding, calender molding and the like for thermoforming, but is particularly suitable for calender molding.

The method for producing PVC used as a raw material of the CPVC of the present invention is not particularly limited, and includes, for example, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method. preferable. The reason is that PVC obtained by the suspension polymerization method is obtained as porous fine particles.

The particle size of PVC is 95% of the entire PVC.
Those whose weight% or more falls within the range of 75 to 500 μm are preferred. When the number of fine particles less than 75 μm or coarse particles exceeding 500 μm increases, when the obtained CPVC is thermoformed, the composition tends to vary, so that thermal deterioration occurs during heating and melting, which leads to coloration of the molded body. A compact cannot be obtained.

In the present invention, the method for chlorinating PVC is not particularly limited. For example, chlorination may be performed in any of a suspension state, a solution state, and a solid state. At this time, chlorination can be promoted by heating, irradiating ultraviolet rays, or adding a peroxide as a catalyst. In addition, when performing chlorination reaction in suspension,
When water is used as a medium, a small amount of ketones such as acetone and methyl ethyl ketone may be added to water, or a chlorinated solvent such as trichloroethylene and carbon tetrachloride may be added. If necessary, hydrochloric acid may be added.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Examples 1 to 6, Comparative Examples 1 to 4) A chain transfer agent and PVC whose average degree of polymerization was adjusted by changing the polymerization temperature were polymerized by a suspension polymerization method, as shown in Table 1. PVCs having different average degrees of polymerization were obtained. Obtained PV
C was chlorinated in a water suspension under irradiation with a mercury lamp, and reacted until the average chlorine content reached the value shown in Table 1. After removing hydrochloric acid and residual chlorine generated thereafter, dehydration and drying were performed to obtain CPVC. Using the obtained CPVC, molding processability (melt viscosity, heat resistance, processability) was evaluated with the following composition. Table 1 shows the results.

CPVC for evaluating the above moldability
Is 100 parts by weight of CPVC, 5 parts by weight of a methyl methacrylate / butadiene / styrene copolymer resin, 0.5 parts by weight of a methyl methacrylate resin, 2.0 parts by weight of dibutyltin maleate, and 0.5 parts by weight of butyl stearate. Was used.

[Melt Viscosity] Using a Koka type flow tester (manufactured by Shimadzu Corporation), CPVC was measured at 200 ° C. for 1 mm.
The measurement was performed under a load of 100 kg / cm ² using a dice having a length of φ × 1 mm. As a sample, a sheet was prepared by kneading the above composition with two 6-inch rolls at 200 ° C. for 2 minutes, and the sheet was cut into a size of about 5 mm × 5 mm. The melt viscosity (η) was determined by the following equation. Melt viscosity (η) = πPD ⁴ / 8LQ [where P = measurement pressure (dyne / cm ² ), D = die hole diameter (mm), L = die length (mm), Q = flow rate (cm ³⁾ / Sec). ]

[Heat resistance (soft temperature)] After laminating the above sheets and preheating at 195 ° C for 3 minutes, the pressure is 150 kg / c.
A press plate processed to a thickness of 1 mm by press molding at m ² for 2 minutes was obtained. A test piece is cut out from this plate, and JIS K
The test method was based on the 6.545 softening temperature (softening temperature) test method for 6745 “hard vinyl chloride plate”.

[Workability] 1) Sheet surface properties The above composition was applied to 200 ° C. × 2 with two 6-inch rolls.
The surface of the sheet prepared by kneading for minutes was observed with the naked eye.
Those at the intermediate level were marked with “△”. 2) Around the bank The state (around the bank) of the sheet wound around the roll during the sheet production was visually observed, and evaluated in order from good to “good”, “Δ”, and “x”. 3) Adhesive When taking out the sheet, "○" indicates that the sheet and the roll surface are easily peeled off, "X" indicates that the sheet is sticky and hardly peeled off.
Those with slight adhesion were marked with "△".

The average degree of polymerization of PVC and the average chlorine content of CPVC were determined by the following methods. (Average degree of polymerization of PVC) Measured according to 3.1 specific viscosity of JIS K 6721 "Testing method for vinyl chloride resin",
The average degree of polymerization was calculated. (Average chlorine content of CPVC) JIS K 7229
It was measured according to the oxygen flask combustion method of "Method for Quantifying Chlorine in Chlorine-Containing Resin", and the average chlorine content in the resin was shown by weight%.

[0024]

[Table 1]

[0025]

The CPVC of the present invention is obtained by limiting the average degree of polymerization of the raw material PVC to a range of 450 to 600.
CP having a high average chlorine content of 68.0 to 72.0% by weight
Despite being VC, the melt viscosity at 200 ° C. can be controlled within a moldable range, and a molded article having good thermoformability and excellent heat resistance can be obtained.

Claims (3)

[Claims] 1. A chlorinated vinyl chloride resin obtained by chlorinating a vinyl chloride resin, wherein the average chlorine content is 68 to
The melt viscosity at 200 ° C. is 8 × 10 ⁴ at 72% by weight.
A chlorinated vinyl chloride resin for thermoforming, characterized in that the resin has a viscosity of up to 20 × 10 ⁴ poise. 2. The chlorinated vinyl chloride resin according to claim 1, which is used for calender molding. 3. The average degree of polymerization of the vinyl chloride resin is 450.
The chlorinated vinyl chloride resin according to claim 1 or 2, wherein