JP2002145977A - Cross-linked vinyl chloride resin foam and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cross-linked vinyl chloride resin foam having an excellent mechanical strength and heat insulating properties and a microcell structure without causing inflow or absorption of a large amount of an adhesive, etc., into cells when the adhesive, etc., are coated. SOLUTION: This cross-linked vinyl chloride resin foam is obtained by including a tin laurate organometallic compound and/or a tin maleate organometallic compound and/or a tin laurate maleate organometallic compound in an expandable composition comprising a vinyl chloride resin, an acid anhydride, an isocyanate, a blowing agent, etc., and expanding the resultant mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crosslinked vinyl chloride resin foam and a method for producing the same. More specifically, a crosslinked vinyl chloride-based material having a fine cell structure that can be suitably used as a core material for ships, windmill blades, and the like, and also as a heat insulating material for liquefied natural gas storage tanks, liquefied natural gas transport tankers, and refrigerated vehicles. The present invention relates to a resin foam and a method for producing the same.

[0002]

2. Description of the Related Art Crosslinked vinyl chloride resin foams are excellent in compressive strength, tensile strength, flexural strength, solvent resistance, etc., and are lightweight, and therefore, for example, unsaturated polyester resins containing a large amount of styrene monomer. It is used as a core material of an FRP laminate using a resin, a core material of various laminated boards, and the like.

[0003] Further, since it has excellent heat insulation properties, it is also used as a storage tank for liquefied natural gas, a tanker for transporting liquefied natural gas, a heat insulating material for refrigerated vehicles and the like.

[0004]

However, conventional crosslinked vinyl chloride resin foams generally have an average cell diameter of 1%.
When the unsaturated polyester is cast on the core material made of the crosslinked vinyl chloride resin foam at the time of producing the FRP laminate, the unsaturated polyester becomes a large amount of cells of the core material. When the adhesive is applied to the core material during the production of the laminated board, a large amount of the adhesive also flows or is absorbed into the cells of the core material, thereby increasing the weight of the final product. In addition, there are disadvantages such as an increase in cost.

As a method for producing the above-mentioned crosslinked vinyl chloride resin foam, for example, vinyl chloride resin, monobasic carboxylic anhydride such as isocyanate, propionic anhydride, isobutyric anhydride, benzoic anhydride, and the like. A method is known in which a foamable composition containing a dibasic carboxylic anhydride such as phthalic acid and a foaming agent is foamed under heat and pressure to produce a primary foam, and then subjected to secondary foaming ( Japanese Patent Application Laid-Open No. 8-208877). However,
The crosslinked vinyl chloride-based resin foam obtained by the above method has a problem that the unsaturated polyester or the adhesive flows into or is absorbed into the cells as described above by increasing the average cell diameter. There was also a problem that the heat insulating property was reduced. As a method for producing the crosslinked vinyl chloride resin foam, the time required for secondary foaming is significantly reduced by adding a tin metal catalyst, and the crosslinked vinyl chloride resin foam is efficiently produced in a short time. Is known (JP-A-8-183870). However, in the tin-based metal catalyst exemplified in the above method, the average cell diameter of the foam is not reduced, and in addition to the problem that the unsaturated polyester or the adhesive flows into the cell or is absorbed as described above, There is a problem that the heat insulating property of the foam decreases.

The present invention has been made in view of the above-mentioned prior art, and when an adhesive or the like is applied, the adhesive or the like does not flow into or absorb into the cell, has excellent mechanical strength, and has excellent heat insulation. It is an object of the present invention to provide a crosslinked vinyl chloride resin foam having excellent properties and a method for producing the foam.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, furthermore, laurate-based tin-based organometallic compounds and / or vinyl chloride-based resins, acid anhydrides, isocyanates, and foaming agents have been added. Alternatively, by foaming the foamable composition using a maleate tin-based organometallic compound and / or a laurate maleate tin-based organometallic compound, the average cell diameter becomes fine, and the adhesive and heat insulating properties are improved. It has been found that an excellent crosslinked vinyl chloride resin foam can be obtained.

[0008] That is, the present invention provides 1) a foam obtained by foaming a foamable composition containing a vinyl chloride resin, an acid anhydride, an isocyanate, and a foaming agent, comprising a laurate tin organometallic compound; And / or a maleate tin organometallic compound and / or a laurate maleate tin organometallic compound, whereby the foam has an average cell diameter of 0.1 mm to 1 mm. The present invention relates to a vinyl resin foam.

Further, the present invention provides 2) an average cell diameter of 0.2
The crosslinked vinyl chloride-based resin foam according to the above 1), which is from 0.1 to 0.8 mm.

Further, the present invention provides 3) a vinyl chloride resin;
A foamable composition containing an acid anhydride; an isocyanate; a laurate tin organometallic compound and / or a maleate tin organometallic compound and / or a laurate maleate tin organometallic compound; The present invention relates to a method for producing a crosslinked vinyl chloride resin foam according to the above 1) or 2), wherein the foam is subjected to primary foaming by pressure and then secondary foaming in the presence of hot water or steam.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Examples of the vinyl chloride resin include copolymers such as vinyl chloride homopolymer and vinyl chloride-vinyl acetate copolymer, as well as vinyl chloride homopolymers and copolymers. In addition, the concept includes a mixture of a resin exhibiting compatibility with vinyl chloride in an inferior amount.

Resins usually referred to as blend resins such as chlorinated vinyl chloride resins, chlorinated polyethylenes and ethylene-vinyl acetate copolymers are resins which can be mixed with the vinyl chloride homopolymers and copolymers. As desirable.

The degree of polymerization of the vinyl chloride resin is as follows:
Usually 1000 to 4000, preferably 1500 to 30
00 is desirable.

Further, among the vinyl chloride resins,
The paste vinyl chloride-based resin can be a so-called sol-like foamable composition having fluidity, and can be suitably used because it may be industrially convenient to handle.

Here, the above-mentioned paste vinyl chloride resin is an almost spherical fine powder having a particle diameter of several μm or less, which is produced by a so-called emulsion polymerization method or microsuspension polymerization method. Fine powder is composed of many fine particles having a smaller diameter. It is desirable that the content of the vinyl chloride resin is 20 to 90% by weight, preferably 30 to 70% by weight, based on the foamable composition.

If the content is less than 20% by weight, the cell membrane of the foam tends to be broken at the time of foaming. If the content exceeds 90% by weight, the density of the foam tends to be too large and the value as a lightweight structural material tends to be lost. There is.

Examples of the acid anhydride include monobasic carboxylic anhydrides such as propionic anhydride, isobutyric anhydride and benzoic anhydride, and dibasic carboxylic anhydrides such as phthalic anhydride and maleic anhydride. These may be used alone or in combination of two or more.

The amount of the monobasic carboxylic anhydride differs depending on whether the monobasic carboxylic anhydride and the dibasic carboxylic anhydride are used in combination, and cannot be determined unconditionally. .

When the monobasic carboxylic anhydride is used alone without using the monobasic carboxylic anhydride and the dibasic carboxylic anhydride in combination, the monobasic carboxylic anhydride may be used. The addition amount is desirably 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the vinyl chloride resin. If the amount is less than 1 part by weight, the crosslinking effect cannot be sufficiently exerted. If the amount exceeds 100 parts by weight, the foaming rate becomes too high and the cell membrane tends to be broken.

When the dibasic carboxylic anhydride is used alone without using the monobasic carboxylic anhydride and the dibasic carboxylic anhydride in combination, the dibasic carboxylic anhydride may be used. The addition amount is desirably 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the vinyl chloride resin. If the amount is less than 1 part by weight, the crosslinking effect cannot be sufficiently exerted. If the amount exceeds 100 parts by weight, the foaming rate becomes too high and the cell membrane tends to be broken.

When the monobasic carboxylic acid anhydride and the dibasic carboxylic acid anhydride are used in combination, the ratio of the added amount of the monobasic carboxylic acid anhydride to the dibasic carboxylic acid anhydride (1 (Basic carboxylic anhydride / dibasic carboxylic anhydride) is preferably from 25/75 to 5/95.

When the monobasic carboxylic anhydride and the dibasic carboxylic anhydride are used in combination, the total amount of the monobasic carboxylic anhydride and the dibasic carboxylic anhydride is 1 to 100 parts by weight of vinyl resin
It is desirable that the amount be 100 parts by weight, preferably 5 to 80 parts by weight. If the amount is less than 1 part by weight, the crosslinking effect cannot be sufficiently exerted. If the amount exceeds 100 parts by weight, the foaming rate becomes too high and the cell membrane tends to be broken.

Examples of the isocyanate include toluene diisocyanate (TDI), diphenylmethane diisocyanate (monomeric MDI), and polymethylene polyphenyl polyisocyanate (polymeric MD).
I), xylylene diisocyanate, hexamethylene diisocyanate and the like. These isocyanates are usually used alone or in combination of two or more.

When the foamable composition is heated in a molding die, the isocyanate dissolves and dissolves the vinyl chloride resin in the order of molecular size, so that the isocyanate and the vinyl chloride resin become entangled with each other. become.

As a result, when the isocyanate reacts with the acid anhydride and water at the time of foaming, the vinyl chloride resin is physically incorporated into the crosslinked chains, and the obtained foam is made of vinyl chloride. The polymer chain of the resin-based resin and the crosslinked polymer chain formed by the reaction with isocyanate, acid anhydride, and water are entangled with each other, and a part of the crosslinked polymer chain is grafted on the polymer chain of the vinyl chloride resin. It is said to be bonded or the like, and has excellent properties such as solvent resistance, heat resistance, and mechanical strength.

The amount of the isocyanate to be added depends on the amount of the vinyl chloride resin 1 in order to sufficiently exhibit a crosslinking effect.
It is desirably 10 to 100 parts by weight, preferably 20 to 80 parts by weight, based on 00 parts by weight. If the amount is less than 10 parts by weight, the crosslinking effect cannot be sufficiently exhibited, and if it exceeds 100 parts by weight, the crosslinking reaction tends to take a long time. The isocyanate generates carbon dioxide gas at the same time as the crosslinking reaction proceeds, and such carbon dioxide gas can be used as a foaming agent.

In the present invention, the laurate tin organometallic compound, the maleate tin organometallic compound, and the laurate maleate tin organometallic compound can be used alone or in combination with two or more.
More than one species can be used in combination.

Examples of the laurate-based organometallic compounds include dibutyltin dilaurate, dimethyltin dilaurate and dioctyltin dilaurate. Examples of the maleate tin metal organic compound include dibutyltin maleate, dimethyltin maleate,
Dioctyl tin maleate, dibutyl tin dimethyl maleate, dimethyl tin dimethyl maleate, dioctyl tin dimethyl maleate, dibutyl tin dibutyl maleate, dimethyl tin dibutyl maleate, dioctyl tin dibutyl maleate, dibutyl tin dioctyl maleate, dimethyl tin dioctyl maleate Eate, dioctyl tin dioctyl maleate and the like.

Examples of the laurate maleate-based tin-based organometallic compound include dibutyltin laurate methyl maleate, dibutyltin laurate butyl maleate, and the like.
And dibutyltin laurate octyl maleate.

The amount of the laurate tin organometallic compound and / or the maleate tin organometallic compound and / or the laurate maleate tin organometallic compound is determined in order to sufficiently reduce the average cell diameter. Preferably, the amount is 0.01 to 5 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount is less than 0.01 part by weight, the average cell diameter tends to be insufficiently refined. If the amount exceeds 5 parts by weight, the effect is not remarkably improved, leading to an increase in cost.

A foaming agent is added to the foamable composition. Such a foaming agent is roughly classified into a decomposable foaming agent and an evaporative foaming agent, and any of the foaming agents may be used in the present invention. preferable.

Examples of the decomposition type foaming agent include azobisisobutyronitrile, azodicarbonamide, diazoaminobenzene, N, N'-dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazide and the like. The blowing agents may be used alone or in combination of two or more.

Examples of the evaporating foaming agent include propane, butane, and chlorofluorocarbon such as chlorofluorocarbon-123. These foaming agents may be used alone or in combination of two or more. Among these, it is preferable to use propane, butane, or the like, which has a small effect on ozone layer destruction.

The amount of the foaming agent to be added cannot be determined unconditionally because it varies depending on the amount of the isocyanate and the acid anhydride to be added, the desired expansion ratio and the type of the foaming agent.

The amount of the foaming agent to be added is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the vinyl chloride resin in order to impart a desired expansion ratio to the foam. It is desirable that the amount is 3 to 7 parts by weight, more preferably 0.5 to 6 parts by weight. If the amount is less than 0.1 part by weight, the desired expansion ratio cannot be imparted to the foam, and
If the amount exceeds the weight part, the foamable composition tends to leak from the molding die during multi-stage pressing, or the cell membrane tends to break during foaming.

The foaming agent can be used in combination with a foaming aid such as urea if necessary. If necessary, a stabilizer, a nucleating agent, a pigment and the like may be appropriately added to the foamable composition as long as the object of the present invention is not hindered. The stabilizer is not particularly limited as long as it has an ability to prevent decomposition and degradation of the vinyl chloride resin. The average cell diameter is 0.1.
It is desirable that it is 1 mm to 1 mm, preferably 0.2 to 0.8 mm, and more preferably 0.3 to 0.7 mm.
If it is less than 0.1 mm, the compressive strength tends to decrease, and if it exceeds 1 mm, when an adhesive or the like is applied,
A large amount of the adhesive or the like flows into or is absorbed into the cell,
In addition, the heat insulating property tends to decrease.

Specific examples of such a stabilizer include, for example, dibasic lead stearate, dibasic lead phosphite, dibasic lead phosphate, dibasic lead phthalate, tribasic lead sulfate and zinc stearate. Examples include calcium stearate, barium stearate, lead phosphite, barium-cadmium-zinc complex, lead-barium complex, barium-tin complex, magnesium oxide, and the like. These stabilizers may be used alone or in combination of two or more. Are used as a mixture.

Examples of the nucleating agent include talc, calcium carbonate, hydrazodicarbonamide and the like, and these nucleating agents are used alone or as a mixture of two or more.

The above-mentioned pigment is for coloring the obtained foam into a desired color. In addition to a white pigment which can also serve as an inorganic filler such as calcium carbonate, for example, titanium white , Benzidine orange, benzidine yellow, watching red and the like.

It is desirable that the foamable composition is sufficiently kneaded using a kneading machine such as a double-arm kneader before filling it into a molding die, thereby forming a sol having a uniform composition. In addition, the temperature at the time of kneading is not particularly limited, and usually may be room temperature.

Next, the foamable composition thus prepared is filled in a molding die made of, for example, an aluminum alloy, and the molding die is set in, for example, a hydraulically driven multi-stage hot press machine. The mold is closed, clamped and heated.

The heating temperature varies depending on the constituents of the foamable composition, but may be an appropriate temperature in accordance with the type and amount of the foaming agent in the foamable composition, for example, 100 to 200 ° C.
Preferably 140-190 ° C, more preferably 150
It is desirable that the temperature be 180 ° C.

When the foamable composition is heated to the above-mentioned heating temperature, the foamable composition is usually 50 to 350 kg / cm.
^{About 2} · G, preferably 100 to 300 kg / cm ² · G
Degree, more preferably 150 to 250 kg / cm ^2.
It has a pressure of about G.

When the heating temperature reaches the above-mentioned temperature range, it depends on the shape of the molding die and the like.
It is desirable to maintain that state for about 50 minutes.

Next, the temperature of the pressurized heating plate of the press machine is cooled to a room temperature or a temperature near the room temperature by using a cooling medium such as water while the molding die is kept pressed, and the molding die is opened. By doing so, a primary foam is obtained.

The acid anhydride in the foamable composition does not directly react with the isocyanate, but becomes a carboxylic acid in the presence of water, and the resulting carboxylic acid reacts with the isocyanate. Therefore, the obtained primary foam is brought into contact with hot water or steam to advance the reaction, and at the same time, secondary foaming is performed by the generated carbon dioxide gas.

In this case, the temperature of the hot water or steam is set at 8 in order to allow the reaction and secondary foaming to proceed sufficiently.
It is desirably about 0 to 130 ° C, preferably 85 to 110 ° C, and more preferably 90 to 100 ° C. If the temperature is lower than 80 ° C., the foam does not foam to a desired expansion ratio, or even if foaming takes a long time for secondary foaming, and if it exceeds 130 ° C., the cell membrane tends to be broken. There is.

The foam thus obtained has high hardness and, of course, excellent mechanical properties,
Since it has a fine cell structure, it can be suitably used as a core material for ships and the like that require light weight and a heat insulating material for refrigeration vehicles and the like that require heat insulation.

[0049]

Next, a method for producing a crosslinked vinyl chloride resin foam having a fine cell structure according to the present invention will be described in detail with reference to Examples. However, the present invention is not limited to only these Examples. .

Examples 1 to 3 and Comparative Example 1 Raw materials were prepared so as to have the compositions shown in Table 1, and the total amount was 75%.
After measuring to 0g, the effective volume is 650ml
The mixture was kneaded at room temperature for 5 minutes in a double-arm kneader to obtain a foamable composition.

The obtained foamable composition has an inner size of 100 mm.
The mold was filled in an aluminum alloy mold having a size of 100 mm x 20 mm, set in a press machine, and the mold was sealed and clamped.

Steam was passed through a hot plate of the press, the temperature of the molding die was raised to 175 ° C., and the pressure was 170 kg / cm ² · G.
And then cooled to 30 ° C. or lower by passing industrial water through a hot plate for press, releasing the tightening pressure of the press, and opening the molding die to obtain a primary foam. The dimensions of the obtained primary foam are 130mm x 130mm x 27m
m. Thereafter, the primary foam was secondary foamed in hot water at 95 ° C. Next, the obtained secondary foam was
It was placed in industrial water at 0 ° C., left standing for 30 minutes, cooled, taken out, and air-dried to obtain a crosslinked vinyl chloride resin foam.

Next, the crosslinked vinyl chloride resin foam was cut into a size of 100 mm × 100 mm × 25 mm using a slicer.
mm, and the density, the average cell diameter and the thermal conductivity were examined according to the following methods. The results are also shown in Table 1. (B) Density The density is determined by measuring the weight (g) and volume (cm ³ ) of the secondary foam. (B) Average cell diameter The cross section of the foam was scanned with a scanning electron microscope (manufactured by Hitachi, Ltd.
(Model number: S-450)
Photographs are copied with a dry copier.

An average value per cell is calculated by drawing 10 straight lines including 3 to 5 cells on the copied screen and dividing the line length by the number of cells included in each line. And determine the average cell diameter. (C) Thermal conductivity A sample of 100 mm × 100 mm × 25 mm was cut out and measured at a temperature of 20 ° C. according to JIS A 9511.

The abbreviations in the table mean the following.

PSH-31: Paste vinyl chloride resin (Kanebuchi Chemical Industry Co., Ltd., average degree of polymerization: 1700) PA: phthalic anhydride PP: propionic anhydride TDI: tolylene diisocyanate MDI: polymethylene polyphenyl polyisocyanate AIBN: azobisisobutyronitrile ACA: azodicarbonamide SL: dibasic lead stearate CC: calcium carbonate BL: dibutyltin dilaurate

[0057]

[Table 1] From the results shown in Table 1, according to the methods of Examples 1 to 3,
Compared to the method of Comparative Example 1, it can be seen that the average cell diameter becomes finer, and the value of the thermal conductivity is accordingly reduced, and the heat insulating property is improved.

[0058]

According to the present invention, when an adhesive or the like is applied, the adhesive or the like does not flow into or absorb into the cell in a large amount, and has excellent mechanical strength and excellent heat insulation. It can be used as a core material for ships, windmill blades, etc., and also as a heat insulating material for liquefied natural gas storage tanks, liquefied natural gas transport tankers, refrigerated vehicles, etc. It is possible.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 BD041 BD051 BD081 EF126 EQ019 ER007 ER019 ES009 EV269 EZ018 EZ048 FD329 4J034 BA01 CA21 CA22 CA24 CB01 CB03 CC01 CC02 CC12 GA15 HA01 HA06 HA07 HC01 HC03 HC12 HC11 HC64 KA01

Claims (3)

[Claims] 1. A foam obtained by foaming a foamable composition containing a vinyl chloride resin, an acid anhydride, an isocyanate, and a foaming agent, comprising a laurate-based organometallic compound and / or a maleate-based tin compound. By containing an organometallic compound and / or a laurate maleate-based tin-based organometallic compound, the foam can have an average cell diameter of 0.1%.
A crosslinked vinyl chloride-based resin foam characterized by having a thickness of 1 mm to 1 mm. 2. The crosslinked vinyl chloride resin foam according to claim 1, wherein the average cell diameter is 0.2 mm to 0.8 mm. 3. An acid anhydride; an isocyanate; a laurate tin organometallic compound and / or a maleate tin organometallic compound and / or a laurate maleate tin organometallic compound; and a blowing agent. 3. The crosslinked vinyl chloride-based resin according to claim 1 or 2, wherein the foamable composition containing the polymer is heated and pressurized to cause primary foaming, and then subjected to secondary foaming in the presence of hot water or steam. A method for producing a foam.