JPH05295155A - Thermoplastic resin foam manufacturing method - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing a thermoplastic resin foam using a foaming agent that does not destroy the ozone layer. [Structure] As a blowing agent, a chain hydrofluoroheptane, a chain perfluoroheptane, which is a hydrofluorocarbon or a perfluorocarbon containing no chlorine atom,
At least one selected from chain hydrofluorooctane or chain perfluorooctane is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foam of a thermoplastic resin such as a styrene resin or a polyolefin resin, and more specifically to a method of producing a thermoplastic resin foam using a specific foaming agent. Regarding

[0002]

2. Description of the Related Art For foaming of thermoplastic resin, chlorofluorocarbons such as dichlorodifluoromethane (R12) (hereinafter, C
FC) has been used.

[0003]

CFC containing chlorine atom
Has a long life in the troposphere, diffuses into the stratosphere,
Here, since chlorine radicals generated by decomposition due to solar rays cause a chain reaction with ozone to destroy the ozone layer, use restrictions of these conventional CFCs have been enforced. Therefore, instead of these conventional CFCs,
Hydrochlorofluorocarbon (HCFC), which does not easily destroy the ozone layer, and hydrofluorocarbon (HFC) or perfluorocarbon (PFC), which does not destroy the ozone layer because it does not contain chlorine atoms, are being actively searched for alternative CFCs.

[0004] The present invention is a thermoplastic resin foaming that uses a specific HFC or PFC that does not destroy the ozone layer and that can be used as a CFC substitute, satisfying the excellent characteristics of conventional CFCs. It is an object to provide a method for manufacturing a body.

[0005]

According to the present invention, a thermoplastic resin and a foaming agent are mixed under high temperature and high pressure and extruded into a low pressure zone,
In the method for producing a thermoplastic resin foam, it is preferable to use at least one selected from chain hydrofluoroheptane, chain perfluoroheptane, chain hydrofluorooctane, or chain perfluorooctane as a foaming agent. A method for producing a characteristic thermoplastic resin foam.

In the present invention, at least one selected from chain hydrofluoroheptane, chain perfluoroheptane, chain hydrofluorooctane, or chain perfluorooctane (hereinafter referred to as a specific fluorocarbon) is used as the foaming agent. It is important to use. Specific fluorocarbons include C7 FH15, C7 F2 H14,
C7 F3 H13, C7 F4 H12, C7 F5 H11, C7 F6
H10, C7 F7 H9, C7 F8 H8, C7 F9 H7, C
7 F10H6, C7 F11H5, C7 F12H4, C7 F13H
3, C7 F14H2, C7 F15H, C7 F16, C8 FH1
7, C8 F2 H16, C8 F3 H15, C8 F4 H14, C8
F5 H13, C8 F6 H12, C8 F7 H11, C8 F8 H1
0, C8 F9 H9, C8 F10 H8, C8 F11 H7, C8
F12H6, C8 F13H5, C8 F14H4, C8 F15H3
, C8 F16 H2, C8 F17 H, or C8 F18 are preferred.

The blowing agent used in the method for producing a thermoplastic resin foam of the present invention is HFC or P which does not destroy the ozone layer.
It is composed of at least one selected from the specific fluorocarbons of FC, has the same characteristics as conventional CFCs, can be used in the same way, and has the advantages of not requiring major changes to the conventional technology.

If necessary, other components may be further added to and mixed with the foaming agent of the present invention. Other components include hydrocarbons such as propane, butane, pentane, isopentane, hexane, isohexane, neohexane, heptane, isoheptane, 2,3-dimethylbutane and cyclopentane, and halogenated hydrocarbons such as chloromethane and dichloromethane. And ethers such as isopropyl ether.

As other components, trifluoromethane (R23), difluoromethane (R32), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,1. 2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,2-difluoroethane (R152), 1,1-difluoroethane (R152)
a), HFC such as monofluoropropane, difluoropropane, trifluoropropane, tetrafluoropropane, pentafluoropropane, hexafluoropropane, heptafluoropropane, or tetrafluoromethane (R14), hexafluoroethane (R11)
6), PFCs such as octafluoropropane (R218), hexafluorocyclopropane (C216) and octafluorocyclobutane (C318).

Furthermore, trichlorofluoromethane (R11), dichlorodifluoromethane (R12),
CFCs such as 1,1,2-trichloro-1,2,2-trifluoroethane (R113), 1,2-dichlorotetrafluoroethane (R114) and monochloropentafluoroethane (R115), or dichloromonofluoromethane ( R21), chlorodifluoromethane (R2
2), 1,1-dichloro-1-fluoroethane (R14
1b), 1-chloro-1,1-difluoroethane (R1
42b), 2,2-dichloro-1,1,1-trifluoroethane (R123), 1,2-dichloro-1,1,2
-Trifluoroethane (R123a), 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R
225ca), 1,3-dichloro-1,1,2,2,3
-Pentafluoropropane (R225cb), 3-chloro-1,1,2,2-tetrafluoropropane (R24
4ca), 1-chloro-1,2,2,3-tetrafluoropropane (R244cb), 3-chloro-1,1,
2,2,3-Pentafluoropropane (R235c
a), HCFC such as 1,1-dichloro-1,2,2-trifluoropropane (R243cc) may be exemplified as the other component.

The total amount of the foaming agent in the present invention is not particularly limited, but is preferably 0.1 part by weight to 50 parts by weight, particularly preferably, 100 parts by weight of the thermoplastic resin.
Used at 5 to 30 parts by weight. The content ratio of at least one selected from the specific fluorocarbons, which is an essential component of the present invention, is 30 parts by weight or more, preferably 70 parts by weight or more.

As the thermoplastic resin in the present invention, a wide variety of known or well-known thermoplastic resins can be used, but styrene resins and polyolefin resins are preferable.

Examples of the styrene-based resin include polymers or copolymers of styrene-based monomers and copolymers of styrene-based monomers with other monomers. Here, examples of the styrene-based monomer include styrene, α-methylstyrene, vinyltoluene, and chloromethylstyrene, and examples of the other monomer include divinylbenzene, acrylonitrile, and methyl methacrylate. Examples thereof include vinyl monomers.

Examples of the polyolefin resin include ethylene homopolymers such as low or high density polyethylene, ethylene copolymers such as ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-vinyl chloride copolymer, ethylene. -Methyl methacrylate copolymer,
Examples thereof include ethylene-acrylonitrile copolymer and polypropylene.

Further, in the present invention, silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, fatty acid metal salts such as barium stearate, zinc stearate,
Various additives such as aluminum stearate and calcium stearate can also be used.

[0016]

EXAMPLES In the following examples and comparative examples, 30 m
Foams were made using a single screw extruder with m diameter. The screw of this extruder consists of a feed zone, a compression / melt zone, a metering zone and a mixing zone. The extruder barrel between the metering area and the mixing area is
An inlet for the foaming agent is provided. This inlet has
A high pressure constant volume pump is connected to inject the blowing agent. The discharge end of the extruder is equipped with a die having a round hole with a diameter of 5 mm.

As the thermoplastic resin, "Dialex HH102" (trade name) polystyrene resin (PS) manufactured by Mitsubishi Monsanto, "F-1920R" (trade name) polyethylene resin (PE) manufactured by Asahi Dow, and Mitsubishi Yuka "Nobren MH8" (trade name) polypropylene resin (P
P) were used respectively. Calcium stearate as an additive is added to 100 parts by weight of each resin.
Parts by weight and 0.5 parts by weight of talc were mixed in a V mixer and supplied from the hopper of the extruder. On the other hand, various foaming agents were injected from the injection port of the extruder barrel using the above high-pressure constant-volume pump, and the resin and the foaming agent were mixed under high pressure and high temperature in the extruder and extruded from the die to foam. .

As the foaming agent, C7 FH15, C7 F2 H
14, C7 F3 H13, C7 F4 H12, C7 F5 H11, C7
F6 H10, C7 F7 H9, C7 F8 H8, C7 F9 H7
, C7 F10H6, C7 F11H5, C7 F12H4, C7
F13H3, C7 F14H2, C7F15H, C7 F16, C8
FH17, C8 F2 H16, C8 F3 H15, C8 F4 H14,
C8 F5 H13, C8 F6 H12, C8 F7 H11, C8 F8
H10, C8 F9 H9, C8 F10H8, C8 F11H7, C
8 F12H6, C8 F13H5, C8 F14H4, C8 F15H3
, C8 F16 H2, C8 F17 H, or C8 F18 were used.

In order to evaluate the foamability, foams were produced using conventional CFCs R12, R114, and R11, and comparison was made with them. The surface of the foam in Tables 1 and 2 was compared with the surface of the foam for wrinkles, unevenness, and the like. In addition, the foam shape is
The cross section of the foam was observed with the naked eye using a magnifying glass, and the ones with comparable independence of cells, uniformity of cell size, etc. were marked with ◯.

[0020]

[Table 1]

[0021]

[Table 2]

In Examples 1 to 34, when the amount of the blowing agent injected was changed to 40 parts by weight for evaluation, similar results were obtained. Moreover, in Examples 1 to 34, the resin type is set to P.
When the evaluation was performed in place of E and PP, similar results were obtained. Furthermore, in Examples 1 to 34, the resin type is PE,
When the evaluation was performed in place of PP and the blowing agent injection amount was changed to 40 parts by weight, similar results were obtained. In the case of PE, R114 was used as the foaming agent of the comparative example, and in the case of PP, R11 was used as the foaming agent of the comparative example.

[0023]

The blowing agent used in the method for producing a thermoplastic resin foam of the present invention is HFC or PFC that does not destroy the ozone layer, chain hydrofluoroheptane, chain perfluoroheptane, chain hydrofluorooctane. , Or at least one selected from linear perfluorooctane
It consists of seeds, has the same characteristics as the conventional CFC, can be used in the same way, and has the advantages that it does not require a significant modification of the conventional technology.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Minako Aoyagi Minako Aoyagi 3-474-2 Tsukakoshi, Sachi-ku, Kawasaki City, Kanagawa Prefecture Asahi Glass Co., Ltd. Tamagawa Branch Room (72) Kenro Kitamura 1150 Hazawa-machi, Kanagawa-ku, Yokohama Asahi Glass Co., Ltd. Central Research Center

Claims (2)

[Claims] 1. A method for producing a thermoplastic resin foam by mixing a thermoplastic resin and a foaming agent under high temperature and high pressure and extruding into a low pressure zone, wherein a chain hydrofluoroheptane or chain perfluoroheptane is used as the foaming agent. A method for producing a thermoplastic resin foam, which comprises using at least one selected from a chain-like hydrofluorooctane, and a chain-like perfluorooctane. 2. A chain hydrofluoroheptane, a chain perfluoroheptane, a chain hydrofluorooctane, or a chain perfluorooctane is C7 FH15 or C7 F2 H.
14, C7 F3 H13, C7 F4 H12, C7 F5 H11, C7
F6 H10, C7 F7 H9, C7 F8 H8, C7 F9 H7
, C7 F10H6, C7 F11H5, C7 F12H4, C7F
13H3, C7 F14H2, C7 F15H, C7 F16, C8 F
H17, C8 F2 H16, C8 F3 H15, C8 F4 H14, C
8 F5 H13, C8 F6 H12, C8 F7 H11, C8 F8 H
10, C8 F9 H9, C8 F10 H8, C8 F11 H7, C8
F12H6, C8 F13H5, C8 F14H4, C8 F15H3
C8 F16 H2, C8 F17 H, or C8 F18.