JPH02182735A - Chlorinated vinyl chloride resin composition pellet, preexpanded particle composed thereof and production thereof - Google Patents

Abstract

PURPOSE:To obtain pellets capable of providing foams excellent in dimensional stability when used at high temperature, i.e., heat resistance with high melt sticking ratio by blending CPVC with a solvent and foaming agent. CONSTITUTION:Pellets obtained by blending chlorinated vinyl chloride resin with a solvent having compatibility therewith and a foaming agent. The content of the solvent is 10-200 pts.wt. based on 100 pts.wt. chlorinated vinyl chloride resin. An evaporation type foaming agent is used as the foaming agent. The chlorinated vinyl chloride resin is kneaded with the solvent having compatibility therewith to provide the shape of pellets, which are then impregnated with the foaming agent and the preexpanded to afford preexpanded particles having 5-100 times expansion ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a chlorinated vinyl chloride resin (hereinafter referred to as CPVC) composition pellet, pre-expanded particles comprising the same, and a method for producing the same. More specifically, the present invention provides a CPVC composition for obtaining a foam molded product (hereinafter referred to as foam) that has excellent dimensional stability when used at high temperatures, that is, heat resistance, and has an arbitrary shape by in-mold foam molding. The present invention relates to a pellet, pre-expanded particles obtained by foaming the same, and a method for producing the same.

[Prior Art] Since CPVC is a resin with excellent heat resistance and flame retardancy, it has conventionally been expected to use CPVC in the form of a foam as a heat insulating material with high heat resistance and flame retardance.

As conventional methods for manufacturing CPVC foam, an extrusion method as described in Japanese Patent Publication No. 5G-26308 and a pressing method as described in Japanese Patent Publication No. 53-27300 have been proposed. However, in these manufacturing methods, even though plate-shaped foams can be obtained, it is difficult to produce irregularly shaped foams having arbitrary shapes as in the in-mold foaming method.

On the other hand, since CPVC has a high softening temperature, high temperatures are required to develop fusion properties during in-mold foam molding, and conventional molding machines used for in-mold foam molding of polystyrene-based and polyethylene-based resins cannot be used as is. However, there is a problem in that a new molding machine that can withstand high temperatures (usually steam is used as a heat source, so it is high temperature and high pressure at the same time) must be prepared.

Therefore, as a result of intensive research to solve the problems of the prior art as described above, the present inventor discovered a CPVC composition pellet, a pre-61 foamed particle, and a method for manufacturing the same, which can solve the problems, and the present invention has been developed. It was completed.

[Means for Solving the Problems] That is, the present invention provides: (1) CPVC composition pellets containing a foaming agent and a solvent exhibiting FIJ solubility with CPVC; (2) CPVC composition pellets containing a solvent exhibiting compatibility with CPVC.
A method for producing CPVC co-foamed particles characterized by kneading VC pre-foamed particles and a solvent that is compatible with CPVC and CPVC to form pellets, impregnating them with a blowing agent, and then pre-foaming them. Regarding.

[Function] The present invention uses CPVC pre-expanded particles containing a solvent that is compatible with CPVC, which is obtained by foaming a CPVC composition pellet containing a solvent and a foaming agent that are compatible with CPVC. The aim is to solve problems.

That is, by incorporating a solvent that has H compatibility with CPVC in the pre-expanded particles, the fusion properties between the pre-expanded particles are increased, and the softening of the resin is reduced by 8 degrees, making it possible to form polystyrene at a low in-mold foam molding temperature. This makes it possible to scale foams with a high weight ratio using conventional molding machines used for in-mold foam molding of polyethylene resins and polyethylene resins.

[Example] CPVC used in the present invention is not only a resin obtained by chlorinating a vinyl chloride resin, but also a blending resin having a solubility of 10 q with this resin, such as a vinyl chloride resin, a chlorinated polyethylene resin, etc. The concept includes a mixture with seeds in which the amount of blending resin in the mixture is 50% by weight or less.

As the vinyl chloride resin to be chlorinated, in addition to vinyl chloride resin, a copolymer containing 50% by weight or more of vinyl chloride can also be used.

Examples of components other than vinyl chloride in the copolymer include vinyl acetate, vinylidene chloride, and ethylene.

The chlorination method may be any conventionally known method, and for example, a photochlorination method under ultraviolet irradiation is preferably used.

With CPVC, if the average degree of polymerization is too low, the physical properties of the foam may be poor.On the other hand, if the average degree of polymerization is too high, it is difficult to produce it industrially. and the chlorine content is 60-75
% of double volumes, preferably with an average degree of polymerization of 1000 to 30
00 with a chlorine content of 60 to 70%.

The particle size of CPVC may be any size within the range commonly used.

As the solvent used in the present invention, basically any solvent can be used as long as it is compatible with CPVC.

There are several measures of compatibility, but in the present invention, for example, CPVC (average degree of polymerization: 2500, chlorine content q ratio: 67%), 100 parts (parts by weight, same hereinafter), 100 parts of solvent, stabilizer [Bis(di-n-butyltin monolaurate) maleate] This refers to the temperature at which 6 parts of the mixture is kneaded in a Prabender Plastograph and exhibits the maximum torque. In the present invention, it is preferable that the solvent has a temperature of 170° C. or less when exhibiting the maximum torque. Specific examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene, diethylbenzene (hereinafter referred to as DEI3), halogenated hydrocarbons such as 1.2.4-trichlorobenzene, and butyl cellosolve (hereinafter referred to as BC). ), diisobutyl ketone (hereinafter referred to as DIIIK), cyclohexanone (hereinafter referred to as CN
ketones such as isooctyl acetate (hereinafter referred to as 0N), isooctyl acetate (hereinafter referred to as
Examples include esters such as IOA), carbonic acid derivatives such as diethyl carbonate, and phosphorus compounds such as trischloroethyl phosphate.These compounds may be used alone, and 2F! The above may be used in combination.

In order to reduce stress or strain remaining in the pre-expanded particles, it is preferable that the amount of solvent in the CPVC composition pellet be as large as possible; however, if the amount is too large, mutual blocking of the pellets may occur. The content of the solvent depends on the compatibility of the solvent with CPVC, but
In general, it is desirable that the amount of CPVC ROAM (TE to Z is 10 to 2,000 parts, preferably 450 to 500 parts).

In addition, in order to improve the mutual fusion properties of the pre-expanded particles and to lower the softening temperature of the resin during in-mold foam molding, it is preferable that the amount of solvent in the pre-expanded particles is as large as possible; Since shrinkage may occur in the foamed product after in-mold foam molding as the solvent evaporates and disappears, the amount of solvent in the pre-expanded particles should be 1 to 1 to 100 parts of CPVC.
It is desirable that the amount is 200 parts, preferably 5 to 100 parts.

As the evaporative blowing agent used in the present invention, the CPV of the present invention
Basically, any agent can be used as long as it can be impregnated into the C composition pellets, but in order to prevent the blowing agent efficiency from decreasing due to permeation and dissipation of the foaming gas during foaming,
It is preferable that the solvent has a low affinity with the evaporative foaming agent. From this point of view, an evaporative blowing agent suitable for the solvent used is appropriately selected and used. Specific examples of such evaporative foaming agents include fluorinated hydrocarbons such as trichlorofluoromethane, dichlorodifluoromethane, and dichlorotetrafluoroethane, and hydrocarbons such as propane, butane, and pentane. The blowing agent is appropriately used depending on the type of solvent.

The amount of the evaporative foaming agent to be impregnated may be appropriately selected depending on the desired expansion ratio, and the impregnation conditions such as temperature and time m1 may also be appropriately set depending on the amount of impregnation.

As the stabilizer used in the present invention, any stabilizer can be used as long as it has the ability to prevent decomposition and deterioration of CPVC, but among them, butyltin laurate, butyltin maleate, or dibutyltin laurate maleate are used. Particularly suitable are system stabilizers. The amount of the stabilizer added is preferably 1 to 6 parts per 100 parts of CPVC.

In addition, in the present invention, for example, titanium oxide,
Of course, pigments such as ultramarine; antistatic agents such as tertiary amines and alkyl sulfonates, which are commonly used as additives for plastics, may be adjusted as necessary and used.

Next, an example of a method for producing the CPVC composition pellet and pre-expanded particles of the present invention will be explained.

First, powder raw materials are thoroughly mixed at a predetermined temperature using a Henschel mixer, a super mixer, or the like. The mixed powder raw materials are put into a pressurized molder or the like together with the liquid raw materials, and kneaded for a predetermined time to obtain a uniform composition.

After kneading, the mixture is fed to a screw extruder, plunger extruder, etc., and the extruded strands are shredded with a suitable cutter (pelletizer) to form pellets.

The pellet, still containing the solvent, is sealed in a sealed container with a predetermined amount of evaporative blowing agent, and the pellet is heated to a predetermined temperature (usually 10 to 70
℃) for a predetermined time (usually 3 to 15 hours) to impregnate the evaporative foaming agent.

The detailed conditions for this impregnation are appropriately determined depending on the type of CPVC, the type and amount of the solvent, the Type 1 evaporative foaming agent, the desired foaming ratio, and the like.

After impregnation, remove the pellet from the airtight container, steam,
Preliminary foaming is performed by heating using hot water or hot air. Pre-foaming conditions are appropriately determined depending on the type of CPVC, the type and amount of solvent, the type and amount of impregnated evaporative foaming agent, desired expansion ratio, etc.

After adjusting the amount of solvent in the pre-expanded particles to the target amount by air-drying or the like, if necessary, the particles are again impregnated with an evaporative foaming agent and formed into a foam by normal in-mold foam molding.

EXAMPLES Hereinafter, the CPVC composition pellets, pre-expanded particles, and knob method for producing the same according to the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1 - IO The raw materials shown in Table 1 were weighed in the proportions shown in Table 2 so that the total amount was 2500 g. 3g of CPVC was put into a pressure kneader together with a solvent and a stabilizer, and 100~
The mixture was kneaded at 130°C for 30 minutes. This product was fed into a plunger extruder, held at 185°C for 35 minutes, cooled to 70-80°C, and extruded into a strand from a die with an inner diameter of 3 mm. ) was cut into lengths of 2 to 4III+1 to make pellets.

Approximately 10 pellets in an autoclave with an internal volume of 8 g
00g was added, and the evaporative foaming agent was further injected, and the pellet was kept immersed in the evaporative foaming agent at room temperature for the time shown in Table 2.

Next, the pellets were taken out of the autoclave, placed in a stainless steel mesh basket with a lid, and immersed in hot water at the temperature and time shown in Table 2 to pre-foam.

The obtained pre-expanded particles were placed in a polypropylene mesh basket, air-dried at room temperature to adjust the amount of solvent, and the content Q80
It was placed in an autoclave No. 1 together with the evaporative foaming agent. After re-impregnating with the blowing agent by holding at room temperature for the time shown in Table 3, the inner size was 250!1m
Using an aluminum alloy mold having a water vapor passage hole of 250 mm x 25 mm, the foam was molded using a normal in-mold foam molding machine at a molding temperature of 151 degrees as shown in Table 3.

The amount of solvent, amount of blowing agent, and physical properties of the obtained pre-expanded particles, such as the expansion ratio, and the physical properties of the foam, such as the apparent density, expansion ratio, and fusion rate, were measured according to the Knob method described below. The results are shown in Table 3.

(Solvent Port and Amount of Foaming Agent) After 0.5 to 1 g of pre-expanded particles were dissolved in 20 ml of tetrahydrofuran, gas chromatography analysis was performed.

(Apparent Density) Two samples of pre-expanded particles or foam were taken and their weight was determined. 100 m filled with water to about half of all scales
The pre-expanded particles or foam after ffl m measurement were placed in a 1-volume graduated cylinder, and submerged under the water surface using a wire mesh type presser, and the volume was determined from the difference between the scales of the front and rear measuring cylinders.

Apparent density was calculated as weight/volume.

(Foaming ratio) Assuming that the specific gravity of CPVC is 1.8, J, 8/apparent density (
Calculated from

(Fusion rate) The foam is bent and ruptured, the cross section is observed, the number of intraparticle fractures (n) is counted, and the total number of particles (N) that appear on the cross section is calculated.
) was calculated using the formula: (n/N) x 100(%).

[Margin below] Comparative Example 1 The pre-expanded particles obtained in Example 2 were left in a hot air circulation oven at 60° C. for 14 days to volatilize and remove the solvent.

Gas chromatographic analysis was performed in the same manner as in Examples 1 to IO to determine the amount of solvent Jl+, and the amount of residual solvent in the pre-expanded particles was 1.1 parts BC and 1.1 parts CN0N. Re-impregnated with dichlorotetrafluoroethane, 14
When in-mold foam molding was carried out at 0°C, the melting rate of the foam was 2596.

[Effects of the Invention] By using the CPVC composition pellets and pre-expanded particles of the present invention, in-mold foam molding is possible using a normal molding machine, and CPV with a high pipe ratio and excellent heat resistance and flame retardance can be produced.
It is possible to make C foam.

Patent applicant Kanebuchi Chemical Industry Co., Ltd.

Claims (1)

[Scope of Claims] 1. A chlorinated vinyl chloride resin composition pellet containing a foaming agent and a solvent that is compatible with the chlorinated vinyl chloride resin. 2. The chlorinated vinyl chloride resin composition pellet according to claim 1, wherein the content of the solvent is 10 to 2000 parts by weight based on 100 parts by weight of the chlorinated vinyl chloride resin. 3. The chlorinated vinyl chloride resin composition pellets according to claim 1, wherein the blowing agent is an evaporative blowing agent. 4. The chlorinated vinyl chloride resin composition pellet according to claim 1, which contains a stabilizer. 5 Pre-expanded chlorinated vinyl chloride resin particles containing a solvent that is compatible with the chlorinated vinyl chloride resin. 6. The pre-expanded chlorinated vinyl chloride resin particles according to claim 5, wherein the content of the solvent is 1 to 200 parts by weight based on 100 parts by weight of the chlorinated vinyl chloride resin. 7. The pre-expanded chlorinated vinyl chloride resin particles according to claim 5, which contain a blowing agent. 8. The pre-expanded chlorinated vinyl chloride resin particles according to claim 7, wherein the blowing agent is an evaporative blowing agent. 9. The pre-expanded chlorinated vinyl chloride resin particles according to claim 5, which contain a stabilizer. 10. The pre-expanded chlorinated vinyl chloride resin particles according to claim 5, which has an expansion ratio of 5 to 100 times. 11 Chlorinated vinyl chloride resin pre-foaming characterized by kneading chlorinated vinyl chloride resin and a solvent compatible with the chlorinated vinyl chloride resin to form pellets, impregnating the pellets with a blowing agent, and then pre-foaming them. Method of manufacturing particles. 12. The manufacturing method according to claim 11, wherein the blowing agent is an evaporative blowing agent. 13. The manufacturing method according to claim 11, wherein the amount of the solvent kneaded is 10 to 2000 parts by weight per 100 parts by weight of the chlorinated vinyl chloride resin. 14. The manufacturing method according to claim 11, wherein the stabilizer is kneaded with the chlorinated vinyl chloride resin and the solvent.