JPS6028296B2 - Method for manufacturing polyvinyl chloride paste foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a vinyl chloride base into an ideal foam having a high expansion ratio and fine closed cells.

Conventionally, there are two main methods for obtaining vinyl chloride-based foams.

One method is to add a chemical blowing agent to vinyl chloride base to produce foam, and the other is to mechanically incorporate air into vinyl chloride base without adding a blowing agent and retain the air bubbles. This is a method of obtaining foam. However, even with these methods, a method for producing a foam with a high expansion ratio and a high closed cell ratio has not been established. Note that the term "highly foamed" as used herein refers to one having a foaming ratio of 7 times or more. Further, the foaming ratio is the value obtained by dividing the specific gravity of the original paste by the specific gravity of the resulting foam. As described above, the mechanical foaming described above results in a foam with continuous cells, and the foaming ratio is limited to 5 times.

Further, foams using chemical blowing agents can be further classified into methods using organic blowing agents and inorganic blowing agents. However, methods using inorganic blowing agents are very rarely carried out. This is because it is difficult to obtain a uniformly controlled foam. Also, even if produced under very tightly controlled conditions, the resulting foams are open-celled or have a high degree of open cell content. Moreover, the expansion ratio is limited to 5 to 6 times. Therefore, methods for producing foams having closed cells are limited to those using organic blowing agents. In order to obtain a foam with a high expansion ratio and closed cells using an organic blowing agent, the type of blowing agent, control of the decomposition temperature of the blowing agent, the type of paste resin, and the type of stabilizer have been studied. There is.

However, the current method is unreasonable in that increasing the foaming ratio will worsen the foaming ratio, and improving the foaming ratio will lower the foaming ratio. This is because the current composition of vinyl chloride bases has a limited ability to retain the gases generated when making foams. Therefore, the present invention uses azodicarbonamide in a vinyl chloride base and further uses an appropriate amount of an allylester thermosetting plasticizer to obtain a foam having a high expansion ratio and a fine and high closed cell ratio. The purpose is to This is because the inventor of the present invention conducted extensive research on various methods of retaining the gas generated when organic blowing agents decompose, and found that the use of thermosetting plasticizers was optimal, and in order to complete the present invention. It has arrived.

Although thermosetting plasticizers are used in solid type PVC pastes, there are no examples of them being used for foaming. One of the reasons for this is that it is difficult to time the curing of the thermosetting plasticizer and the decomposition of the blowing agent in a timely manner. In the present invention, this timing has been successfully adjusted by selecting the resin used, the type and amount of the plasticizer, and the stabilizer. Therefore, in the present invention, an ordinary foamable vinyl chloride base containing azodicarbonamide is added with an allylester thermosetting plasticizer in an amount of 10 to 30%.
This is a manufacturing method that allows foaming by a conventional method with 0 parts by weight added, and according to this invention, a foam with a high expansion ratio that is fine and has a high closed cell ratio can be obtained.

It should be noted that the allylester thermosetting plasticizer can be cured in a short time, and the timing can be easily matched with the foaming of the PVC paste. Further, when using the alreester thermosetting plasticizer, a peroxide may be used as a curing agent. When the above-mentioned thermosetting plasticizers are used in vinyl chloride bases, the viscosity stability of the paste poses a major problem and cannot be used indefinitely.

It goes without saying that the method of use must take into consideration the expansion ratio, foam condition, and storage stability of the vinyl chloride paste. In this way, according to the present invention, the foaming ratio is 8 times to 1 and the thickness is 1 to 15 mm. It is possible to obtain a foam with a high degree of foaming and a high closed cell ratio, something that could not be achieved conventionally.

Therefore, it has the advantage that it has improved thermal insulation properties compared to a closed cell, has strong recovery power because it is a closed cell, is cheap, and can easily be made with high foaming. Next, the present invention will be explained by examples.

Example 1 10 parts by weight of vinyl chloride-based resin (trade name Won121), Murodo part of DOP6, 20 parts by weight of diallyl phthalate (trade name DAP monomer), 3 parts by weight of Zn/Ba-based stabilizer, Azodi Carbon amide (trade name AZ-H) 8 parts by weight, tributyl peroxybenzoate 0. (a) parts by weight are mixed in a conventional manner to obtain a vinyl chloride base.

This paste was evenly applied to a 0.5 plate thickness on an aluminum plate of 0.2 plate thickness, and heated in a 200 qo electric oven for 30 minutes.
A foam with a foaming ratio of 1 and a high closed cell ratio is obtained by curing and foaming. Example 2 The vinyl chloride base prepared in Example 1 was uniformly coated on an aluminum plate to a thickness of 1.3 cm, and cured and foamed in a 20,000 electric oven for 3/3 seconds to achieve a foam thickness of 1 cm. A foam with fine air bubbles is obtained.

It is also possible to obtain thick foam called IQ ribs at high magnification.
This is a major feature of this invention. Example 3 100 parts by weight of vinyl chloride paste resin (Hebi on121), 15 parts by weight of diallyl phthalate (DAP monomer), 3 parts by weight of Ca/Zn/Ba stabilizer, 6 parts by weight of azodicarbonamide (AZ day), 0.15 parts by weight of kinimen hydroperoxide and 2 parts by weight of calcium carbonate are mixed in a conventional manner to obtain a vinyl chloride base.

This paste was coated on the inner surface of a ceramic water storage tank with an inner volume of 20 mm using a slush molding method so as to have a wall thickness of 1.2 mm.
1 by heating and foaming in a 0oo oven for 10 minutes.
To obtain a tank having a uniform foam layer with a high closed cell ratio and a thick wall.

This has a high closed cell ratio and a very light specific gravity, making it a good material for preventing fogging. As described above, according to the present invention, despite the high expansion ratio, a foam with a fine and high closed cell ratio can be obtained, which improves the heat insulation properties and recovery power, and reduces the cost because less materials are required. It is inexpensive and has excellent effects, such as the ability to easily obtain thick insulation layers.

Claims (1)

[Claims] 1 Add appropriate amounts of azodicarbonamide and an allyl ester thermosetting plasticizer to ordinary vinyl chloride paste to obtain a foam paste, and produce a foam using a conventional method to create a foam that has a high expansion ratio and is fine and independent. A method for producing a vinyl chloride paste foam, which is characterized by producing a foam with a high cell content.