JPS61151073A - Manufacture of pollution-free inorganic foam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a method of producing a foam material mainly consisting of a small amount of vinyl chloride resin (PVC) and a large amount of inorganic powder using a chemical blowing agent in the presence of an organic solvent. In doing so, a homogeneous structure can be achieved by using an organic peroxide, which has traditionally been considered extremely difficult to use in modifying PVC.

In particular, the present invention aims to produce a non-combustible, lightweight foam with excellent mechanical strength and good dimensional stability without using polluting substances such as inorganic fibers such as asbestos, which have been often used in the past. This is a characteristic feature.

<Prior art> As a conventional known technology, for example, Japanese Patent Publication No. 52-28778
In this issue, the blending of inorganic fibers into the 41-free powder prevents a decrease in mechanical strength when exposed to fire and improves dimensional stability.

However, the use of inorganic fibers, especially harmful substances such as asbestos, which is cheap and easy to use, in the foam manufacturing process poses an extremely serious risk to the health of workers during the foam manufacturing process. At the same time, various operations such as construction, cutting, and crushing in the distribution route of the foam inevitably generate dust, which also has the drawback of creating a danger that is harmful to the human body. there were.

It has been known for a long time that when PVC is heated, it is crosslinked while being dehydrochlorinated to obtain a gel-like insoluble content, and this point is also described in the following four documents.

(1) Magazine name ° “Plastic” Vo1.19, N
o, 6 (Hirosuke Kojima), (2) “Polyvinyl chloride: Chemistry and Industry” (Kyocho Shoten), (3) Industrial Chemistry Magazine 58
．． 802 (1953) (cuttings, great rules), (4) Industrial Chemistry Magazine fil.

1382 (1958) (Sobue, Tabata) Like this p.
VC itself has poor heat stability, and as a result it can be said to be a resin that is extremely easy to crosslink, but at the same time, PV
Crosslinking while decomposing C means that the structure of PVC itself deteriorates due to the coloration of the resin itself, the difficulty of controlling crosslinking, the difficulty of controlling the reaction rate, etc., so it is not practical. It is considered inappropriate.

In addition, another document "Vinyl chloride and poly-F-J 7, 11. No. 9
According to the data of (Nakamura), crosslinking is discussed from the gel content in methyl ethyl ketone by adding an organic peroxide such as dicumyl peroxide (DC:P) to PVC and heat-treating it at 120 to 150°C.

Amount used/PVC Insoluble dicumyl peroxide 0.5$ 18.
3-Tertiary Butyl Perbenzoate 1.0$ 38.0 It is reported that the coloring is severe, the permanent deformation rate is large, and the insoluble content is large. However, the fact that PVC is crosslinked and insoluble matter is produced in this way is a phenomenon that is completely opposite to the goal of producing foam by using organic peroxide in PVC. This also negates the possibility of producing foams.

That is, in the crosslinking reaction of PVC, this method can be said to have no practical value because the decomposition of PVC occurs in a violet manner.

Plastics Age, Oct. 1969
(Hirosuke Kojima) describes an example in which crosslinking of a PVC-based composition is industrialized.

One of them is Jobs-Manville in America.
Corp.

There is a method by Kleben Colombs, which uses PVC1 maleic anhydride, a vinyl monomer, a polymerization catalyst,
The method is characterized by producing a foam by heating and pressurizing a mixture of diisocyanates, but in this reaction, vinyl chloride and maleic acid first copolymerize, and then the maleic acid reacts with the diisocyanate to cause crosslinking. This is not crosslinking of PVC itself.

Another example is the use of diallyl ester-based, diacrylic ester-based, unsaturated polyester-based, and epoxy-based plasticizers as reactive plasticizers for PVC (base resin) plastisol. In this case, the purpose of using a reactive plasticizer in plastisol is not to crosslink PVC, but to make a hard product by utilizing the crosslinking reactivity of the reactive plasticizer itself as described above.

In this way, PVC itself has a tID of organic peroxide due to its nature.
, it has been extremely difficult in practice to use tva agents such as alkoxy radicals.

From this technical background, the inventor of the present invention
He completed an invention as shown in Japanese Patent No. 811180 and filed a patent application for it, but the invention did not take into account the use of organic peroxides, which is difficult, and used a catalyst that generates carbon radicals and a catalyst that generates sulfur radicals. The company established a method for producing foam using a small amount of PVC and a large amount of inorganic materials.

<Problems to be Solved by the Invention> The present invention does not require any harmful fibrous substances such as asbestos as described above, and can be used in a composition mainly consisting of a large amount of inorganic powder and a small amount of vinyl chloride resin. , the medium P
Organic peroxide is used as a driving force that acts strongly on the uniform foaming of VC and forms a homogeneous continuous phase of PVC.

The present invention is based on the concept of utilizing the dilution effect of a large amount of inorganic components by using organic peroxides, which have been considered extremely difficult to use in practice for PVC as described above, and by combining both components in a non-crosslinking manner. The aim is to activate the foam to produce a foam.

In other words, as mentioned above, applying an organic peroxide directly to PVC will cause serious damage to the PVC structure.
In the present invention, it has been found that by adding an inorganic component in an amount of 1 to 100 times as large as the pvc i part, it is possible to dilute the action of alkoxy radicals and thereby alleviate the reaction.

As a result, the organic peroxide acts on PVC in a non-crosslinking manner, and at the same time, even on the inorganic components used in large quantities, both the PVC and the inorganic components are activated by bonding the alkoxy radical fragments. It was found that the chemical compatibility of the components increases and at the same time the viscosity of the entire system increases.

Therefore, it has been discovered that the foaming gas generated from the chemical foaming agent can be sufficiently retained in the system and a homogeneous foam can be produced.

PVC is originally an amorphous polymer and swells well with the organic solvent used, but the inorganic components used in large amounts are PVC, an alkoxy radical generated from organic peroxides.
Without degrading the PVC structure by relaxing the dilution effect on the VC, PVC,! :We were able to limit the activation effect to only the bonding with alkoxy radicals.

The dilution effect of this inorganic component sufficiently maintains the function of PVC as a foaming medium, and it has been found that it is actually possible to produce foam from PVC-based compositions using organic peroxides, which was previously thought to be extremely difficult. did. Moreover, it does not use harmful components such as asbestos in inorganic fibers as described in the aforementioned Japanese Patent Publication No. 59-8860,
By improving PVC with a non-polluting chemical substance (organic peroxide), it is possible to produce a foam with excellent mechanical strength and good dimensional stability.

Means for Solving the Problems> Next, the manufacturing method of the present invention will be described as follows.

A large amount of inorganic powder is mixed in a horizontal or vertical kneader at a ratio of 1 to 100 parts to 1 part of a small amount of PVCC (mainly emulsion polymerized amount or base resin), and a chemical blowing agent and an organic peroxide are added to it. Stir to mix evenly.

In order to ensure uniform mixing of the solid components, a high-efficiency, high-speed stirrer such as a Henschel mixer may be used in conjunction with the above-mentioned kneader.

After uniform dispersion of the solid components is achieved, the organic solvent is added in portions. After all raw materials are mixed homogeneously.

The raw material is filled into a mold installed in a multistage hot press and foamed under pressure at a temperature of 100 to 180°C. This is called first stage foaming.

After the first stage of foaming, water cooling, depressurization, and placing in an oven at normal pressure 8
The second stage foaming is carried out at an appropriate temperature of 0 to 120°C.

After this second stage foaming, the organic solvent is removed using a dryer, and the product is finished to a predetermined size using a cutter.

During this manufacturing process, in the kneader, alkoxy radicals are generated from the organic peroxide due to frictional heat between a large amount of inorganic components and PVC, and vinyl chloride resin (PVC) swollen by an organic solvent is used in a large amount of inorganic components. Activation of the PVC and mineral components takes place due to the action of the alkoxy radicals, which is moderated by the dilution effect of the components.

That is, the alkoxy radical extracts hydrogen or chlorine from the PVC structure, and as a result, the chemical modification activation 7 of PVC proceeds in which the generated polymer radical and alkoxy radical are recombined. At the same time, "chemical denaturation activation of inorganic components" in which alkoxy radicals recombine with inorganic components also progresses.

Next, in the pressing process, the raw materials are heated to 100 to 180°C, which further promotes the generation of alkoxy radicals from the organic peroxide and the swelling of PVC by the organic solvent, resulting in the release of both components. As the chemical modification progresses further, the compatibility of both components increases. As a result, the foaming gas within the system is sufficiently retained within the system to produce a uniform foam.

In the above process, PVC undergoes no crosslinking reaction due to the dilution effect of the large amount of inorganic components present in the system, and chemical modification occurs in a non-crosslinking manner. This fact was also proven by the fact that the resulting foam was extracted with methyl ethyl ketone or tetrahydrocran and no gel-like (crosslinked structure) material was present in the PVC extract.

In the present invention, vinyl chloride resin means a homopolymer or a copolymer, and among them, PVC made by emulsion polymerization or solution method is most preferable, but it can also be used by microsuspension method, suspension method, or bulk method. Preferably, the particle size is 50 microns or less.

However, even with ordinary PVC made using the suspension coating method, the
% or less.

Further, copolymer partners include pylidene chloride, vinyl acetate, maleic acid, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, acrylonitrile, methacrylonitrile, styrene, ethylene, and propylene.

Further, as the inorganic component in the present invention, any inorganic powder having a particle size of 70 microns or less can be used, but for example, carbonates of metals such as calcium, magnesium, aluminum, titanium, iron, zinc, etc. Examples include sulfates, silicates, phosphates, borates, oxides, hydroxides, or water products thereof, silica, silicic anhydride, talc, bentonite, clay, etc., and one or more of these can be used. .

The particle size of the inorganic powder is preferably as small as possible, and preferably passes through a sieve of 20 meshes, preferably 80 meshes or more.

The amount used can include 1 to 100 times the weight of the vinyl chloride resin.

In addition, organic solvents in the present invention include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, and chlorobenzene; halogenated hydrocarbons such as ethylene chloride, trichloroethane, and carbon tetrachloride; acetone, methyl ethyl ketone, Examples include ketones such as methyl isobutyl ketone, and these can be used alone or in a mixture of two or more. The amount of the organic solvent used is 30 to 80 parts by weight based on 100 parts by weight of the total amount of vinyl chloride resin and inorganic powder.
Parts by weight are preferred, and the organic peroxides used in the present invention include (1) alkyl peroxide R-0-0-R' tertiary butyl cumyl peroxide wood lauroyl peroxide (3) hydroperoxide R-0 -0-H (Example) This cumyl hydroperoxy 1CH-C-0-
OH H (4) Peroxyketal (Example) 1.1-bis(tertiary-bukel peroxy)-silurohethane (5) Ketone peroxide methyl ethyl ketone peroxide Ogicide (Example) Present Tertiary Butyl Baroquine Isobutyrate One or more of these organic peroxides is used.This organic peroxide is at least 0.0% per 100 parts of polyvinyl resin (PVC). It is necessary to use 1 part by weight or more.

As the chemical blowing agent in the present invention, a generally used thermally decomposable organic blowing agent or inorganic blowing agent is used.

(1) Organic decomposable blowing agents include azodicarbonamide, azobisformamide, PPo
-oxybisbenzenesulfonylhydrazide, P-1 luenesulfonylhydrazide, azobisisobutylnitrile, NN-dinitrosopentamethyleneradramine, NN
'-Dinitroso-NN-dimethylterephthalamide, P
-Toluenesulfonylhydrazide, benzenesulfonylhydrazide, PPo-oxybisbenzenesulfonylhydrazide and foaming aids that adjust the decomposition temperature in combination therewith.

(2) Inorganic decomposable blowing agents include sodium bicarbonate, ammonium carbonate, nitrite, magnesium carbonate, and ammonium persulfate.

Furthermore, in the present invention, PVC heat stabilizers, antioxidants, ultraviolet absorbers, etc. can be added as necessary.

Effects> The present invention uses organic peroxides, which have traditionally been considered extremely difficult to use in modifying PVC, by mitigating the effects of alkoxy radicals generated from them through the diluting action of a large amount of inorganic powder, thereby modifying the structure of PVC. The main feature is that it activates PVc in a nodal cross-linking manner without causing damage.

Furthermore, by increasing the compatibility between the activated inorganic powder and PVC, both components are packed most densely together with the swelling effect of the PVC by the organic solvent, and the foaming gas generated from within the system is sufficiently absorbed into the system. The present invention features a method for producing a foam of a Pvc-based composition by holding.

<Example> Hereinafter, the present invention will be specifically explained with reference to examples.

Made by Nippon Zeon Co., Ltd. 121) 10
0 Calcium carbonate 8゜Talc 7゜Aluminum hydroxide 2゜Ditrosopentamemelenetetramine 6 Foaming aid
B Azobisisobutylnitrile 15 Dicumyl peroxide 7 Tribasic lead sulfate
2 dibasic stearin lead
1 toluene
After stirring the solid components other than 200 toluene for 30 minutes using a horizontal blender, half of the toluene was gradually added, and after stirring for 30 minutes, the remaining amount of toluene was added and stirring was continued for an additional 30 minutes.

During stirring of the raw materials, the temperature of the ingredients was heated to 50-80"C and heated at 100-171"C for 60 minutes.
Foaming was carried out under a pressure of kg/crn'.

This is called first stage foaming. After the first stage foaming was completed, the product was cooled with water for 80 minutes and decompressed, and then the product was taken out.

Next, this was placed in a shelf foaming machine and allowed to freely foam at 100° C. for 60 minutes under normal pressure to complete the second stage foaming. The resulting foam was placed in a tray dryer at 100° C. and dried for 48 hours to remove residual solvent. After drying, the product was cut and sliced into desired dimensions and thickness.

The physical properties obtained were as follows.

The apparent specific gravity is 80kg/m″
Compressive strength 10. l3kg/c
rn' bending strength 10.2k
g,/cm'Thermal conductivity 0.031
kcal/ m m hr 0 linear expansion coefficient
23.5X1G Moisture permeability 0-
00028g/m 6 hr @m m Hg Weather resistance When exposed outdoors for 2 years, there were no cracks on the surface and no deterioration phenomenon was observed.

χ” 11 parts by weight Vinyl chloride resin (base resin, manufactured by Sumitomo Chemical) 100 titanium oxide
120 calcium carbonate
150 poxide powder
150 Azocica-Bonamide
12Azobisisobutyronitrile
16 dicumyl baroxide
51.1 Bis(tert-butylperoxy)3.3.5-)limethylcyclohexane
l Barium stearate
1 Calcium stearate
l toluene 180
Xylene 150 Among the above ingredients, put all the solid raw materials into a Henschel mixer and mix 3
After stirring at high speed for 1 minute, transfer to a horizontal Nigu, add toluene,
A mixed solvent of xylene was added in the same manner as in Example 1. Thereafter, all products were manufactured according to the procedure of Example 1. Its physical property values were as follows.

The apparent specific gravity is 110kg/rrf
Compressive strength 7.0kg/c
rn' bending strength 6.8kg/
C thermal conductivity 0.030 kcal/
m @hr ・'0 linear expansion coefficient 2
3. OX 1G moisture permeability 0.00027g
/ m * hr * m m Hg weather resistance No deterioration was observed after 600 hours of irradiation in the weatherometer test.

Parts by weight of vinyl chloride resin (base resin, Nippon Zeon Co., Ltd. 121) 75
Vinyl chloride, vinyl acetate copolymer resin ("TL Ki Kagaku Kogyo Electric Vinyl M-120")
25 Silicic anhydride 150
Calcium carbonate 250 Talc 200 Azobisisobutyronitrile 18 p-Toluenesulfonyl hydrazide 10 Dinitrosopentamethylenetetramine 6 Foaming aid
6 Dicumyl peroxide 7 Tertiary butyl peroxyisobutyrate 2 Tribasic lead sulfate
3 Dibasic lead stearate
2 toluene
250 ethylbenzene 1
00 A foam was produced using the above components in the same manner as in Example 1.

The physical property values are as follows.

The apparent specific gravity is 120kg/m”
Compressive strength 8.0kg/c
m' bending strength 5.2kg/
cm”Thermal conductivity 0.030 kcal
/ m 11hr * ℃ Linear expansion coefficient
23. OX to' moisture permeability 0.00
027g/m e hr @m m Hg#climate
No deterioration was observed in the Weatherometer test after 700 hours of irradiation.

Parts by weight Vinyl chloride resin (base resin, manufactured by Sumitomo) 100 Calcium carbonate 3000 Talc 2000
Titanium oxide 7 1000 Azobisisobutyronitrile 50 Dinitrosopentamethylenetetramine 30 Foaming aid
30 Dicumyl peroxide 151.1 Bis(tert-butylperoxy)cyclohexane
1 toluene
2000 xylene
A foam was produced using 1000 or more raw materials in the same manner as in Example 2.

The physical properties of the product were as follows.

Appearance is weight! 35kg/m”
Compressive strength 5.0kg/c
m' bending strength 4.5kg/
c m'thermal conductivity 0.032 kcal
/ m m hr * 'C coefficient of linear expansion
21. OX 10 moisture permeability 0.00
028/m a hr m m mHg weather resistance
No crack deterioration was observed in the one year outdoor exposure test.

Ratio n+ (In order to compare with the above example, we attempted a case where no organic peroxide was used. N+ parts by weight Vinyl chloride resin (base resin, Nippon Zeon Co., Ltd. 121) 1
00 Calcium carbonate 110
Talc 100
Dinitrosopentamethylenetetramine 7. Foaming aid 7. Azodicarbonamide 5. Tribasic lead sulfate
4 Dibasic lead stearate 2 Toluene
l [io Although this component was operated in exactly the same manner as in Example 1, it was not possible to obtain a foamed product in the first stage of foaming using a hot press.

In other words, it has been demonstrated that a foam cannot be produced with a system containing a small amount of vinyl chloride resin and a large amount of airless components unless an organic peroxide is added.

! tlL1! u12 (The following test was conducted to confirm the dilution effect of inorganic components.) Vinyl chloride resin (base resin, Nippon Zeon Co., Ltd. 121) 1
00 dinitrosopentamethylenetetramine 7
Foaming aids 7 Tribasic lead sulfate 4 Dibasic lead stearate 2 Tert-butyl peroxide 5 Dicumyl peroxide 7 Toluene
A 60-piece formulation was operated in the same manner as in Example 1, but since no inorganic component was used, there was no dilution effect and the PVC was crosslinked and insolubilized, making it impossible to produce a foam.

<Effects of the invention> The vinyl chloride inorganic foam produced by the present invention has the following properties:
In addition to being lightweight, nonflammable, and non-polluting, it has a closed cell structure, so it naturally has excellent heat insulation properties, as well as good water resistance and sound absorption, as well as a small coefficient of linear expansion and excellent resistance to extremely low temperatures. have.

Due to these properties, it can be used as insulation materials for buildings, axles, insulation materials and sound-absorbing materials for ships, civil engineering work, waterproofing for basements, insulation materials, and even L.
It has extremely excellent performance as a cold insulation material for NG underground tanks, etc., and therefore has characteristics that can contribute to an extremely wide range of fields.

Claims (1)

[Claims] In the method of manufacturing a uniform PVC foaming composition mainly consisting of a small amount of vinyl chloride resin and a large amount of inorganic powder, using a chemical blowing agent and an organic solvent, the gas generated by the chemical blowing agent during manufacturing is In order to retain the foam in the system, the viscosity of the system is increased in the presence of an organic solvent by activating PVC and inorganic powders with alkoxy radicals generated from organic peroxides. A method for producing a non-polluting inorganic foam, which is characterized by making production possible.