JP2000264995A - Vinyl chloride-based resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a vinyl chloride-based resin foam not causing softening deformation and shrinkage even in the case of being superimposed with an FRP plate and capable of exhibiting excellent resistance to solvent, or the like, by foaming a vinyl chloride-based resin so as to have a specific physical properties. SOLUTION: By foaming a foamable composition comprising (A) a chloride- based resin, (B) a carboxylic acid anhydride (e.g. a monobasic or dibasic carboxylic acid anhydride) and (C) an isocyanate compound, the objective foam having a density of 20-80 kg/m3 and >=80% volume retention when immersed in styrene monomer at 80 deg.C for 1 h is produced. The ingredient C is preferably formulated with both polymethylenepolyphenylpolyisocyanate and a polyisocyanate of the formula [wherein, the average of (n) is 1.4]. The formulating amount of the ingredient A is preferably 20-90 wt.% based on the weight of the foamable composition. The formulating amount of the ingredient C is preferably 20-80 pts.wt. based on the ingredient A of 100 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin foam. More specifically, the present invention relates to a vinyl chloride resin foam that can be suitably used as a core material of an FRP laminate used for structural panels such as ships and pools.

[0002]

2. Description of the Related Art Conventionally, a laminated panel in which a rigid polyurethane foam is used as a core material and an FRP plate is laminated on both sides thereof has been used for structural panels for ships, pools and the like.

However, the rigid polyurethane foam used as a core material in the laminate panel is made of FR.
Due to poor adhesion to the P plate, there is a drawback that peeling is likely to occur between them, and that bending strength and compressive strength are low.

In view of the above, there has been proposed a structural panel using a non-crosslinked vinyl chloride resin foam that has not been subjected to a crosslinking reaction as a core material having excellent adhesiveness to an FRP plate.

Although the above structural panel is excellent in the adhesiveness between the FRP plate and the non-crosslinked vinyl chloride resin foam, the non-crosslinked vinyl chloride resin foam is easily softened and deformed and shrinks. There is a disadvantage that it is easy to occur.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above prior art, and does not cause softening deformation or shrinkage even when laminated with an FRP plate. An object is to provide a resin foam.
In particular, a vinyl chloride resin foam containing a vinyl chloride resin, a carboxylic anhydride, an isocyanate compound, and a foamable composition further containing a foaming agent, if necessary, and having more excellent solvent resistance and the like. And an improved foam having the same.

[0007]

According to the present invention, there is provided a foamed vinyl chloride resin having a density of 20 to 80 kg / m ³ and a volume retention ratio after immersion in a styrene monomer at 80 ° C. for 1 hour. Is 80% or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The vinyl chloride resin foam of the present invention is obtained by foaming a vinyl chloride resin as described above, has a density of 20 to 80 kg / m ^3, and has a styrene temperature of 80 ° C. It has a volume retention of 80% or more after being immersed in a monomer for 1 hour.

According to the study of the present inventor, the cause of the softening deformation and shrinkage of the non-crosslinked vinyl chloride resin foam during the production of the structural panel composed of the FRP board and the conventional non-crosslinked vinyl chloride resin foam is as follows. It was found that the styrene monomer was used as a raw material monomer for the FRP plate.
The inventor is a crosslinked vinyl chloride resin foam,
The density is 20 to 60 kg / m ³ , and the area retention after immersion in a styrene monomer at 50 ° C. for 1 hour is 80%.
In the case described above, it was found that softening deformation and shrinkage did not occur when forming a laminate with the FRP plate, and a patent application (Japanese Patent Application Laid-Open No. 9-328567) was filed.
However, in order to shorten the molding time by shortening the reaction time of the styrene monomer during the production of the laminate with the FRP plate, the molding atmosphere temperature may be increased to about 50 ° C. to 80 ° C. instead of the ordinary room temperature. In some cases, deformation and shrinkage were found to occur without improved styrene monmer resistance. In order to enable molding in such a high temperature range, the volume retention of the vinyl chloride resin foam after immersion in a styrene monomer at 80 ° C. for 1 hour is 80%.
%, And as a result of various studies to satisfy this requirement, the present invention has been completed.

[0010] The vinyl chloride resin foam of the present invention includes, for example, vinyl chloride resin, carboxylic anhydride and polymethylene polyphenyl polyisocyanate (hereinafter referred to as MDI).
And general formula (I):

[0011]

Embedded image (Wherein, n is about 1.4 on average) by foaming a foamable composition containing an isocyanate compound comprising a polyisocyanate represented by the following formula:

The vinyl chloride resin includes, for example, copolymers such as vinyl chloride homopolymer and vinyl chloride-vinyl acetate copolymer, and vinyl chloride homopolymer and copolymers. This is a concept including a mixture of inferior amounts of a resin exhibiting compatibility with the above. Resins usually referred to as blend resins such as chlorinated vinyl chloride resins, chlorinated polyethylenes, and ethylene-vinyl acetate copolymers are preferred as resins that can be mixed with the vinyl chloride homopolymers and copolymers. The polymerization degree of the vinyl chloride resin is usually preferably from 1,000 to 4,000, more preferably from 1,500 to 3,000. Also, among the vinyl chloride resins, the paste vinyl chloride resin can be a so-called sol-like foamable composition having fluidity, and is preferably used because industrial handling is convenient. It can be used. Here, the paste vinyl chloride resin is a substantially 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, and the fine powder is further It is composed of a large number of small particles. In order to prevent the cell membrane of the foam from being broken during foaming, the amount of the vinyl chloride resin is preferably at least 20% by weight, more preferably at least 30% by weight, based on the foamable composition. Further, in order to prevent the density of the foam from becoming too large and not to lose its value as a lightweight structural material, 90% by weight or less based on the foamable composition,
In particular, it is preferably at most 60% by weight.

As the isocyanate compound, the aforementioned MD
In addition to I, there are various types such as toluene diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate. In the present invention, MDI and general formula (I):

[0014]

Embedded image (In the formula, n is about 1.4 on average).

When the polyisocyanate represented by the general formula (I) is used in combination with MDI, excellent styrene monomer resistance is imparted to the vinyl chloride resin foam.

The value of the weight ratio of the polyisocyanate represented by the general formula (I) to MDI (polyisocyanate represented by the general formula (I) / MDI) is set to 0.1 in order to improve the styrene monomer resistance. It is desirably 1 or more, preferably 0.2 or more, and more preferably 0.3 or more. In order to make it difficult for cracks to occur during secondary foaming, 3.0 or less, preferably 2.5 or less. , More preferably 2.0 or less.

If necessary, a mixture of MDI and the polyisocyanate represented by the general formula (I) may be blended with another isocyanate compound such as TDI in a range not to impair the object of the present invention, for example, inferior amount of TDI. Can also. The compounding amount of the isocyanate compound is at least 20 parts by weight, preferably at least 25 parts by weight, based on 100 parts by weight of the vinyl chloride resin, in order to improve the moldability by improving the flowability of the foamable composition. More preferably, 3
0 parts by weight or more, and preferably 80 parts by weight or less, preferably 75 parts by weight with respect to 100 parts by weight of the vinyl chloride-based resin, in order to prevent foaming of the obtained vinyl chloride-based resin foam. Parts or less, more preferably 7
It is desirable that the content be 0 parts by weight or less. When the foamable composition is heated in a molding die, the isocyanate compound dissolves the vinyl chloride-based resin and unravels it in the order of molecular size, so that the isocyanate compound and the vinyl chloride-based resin become entangled. As a result, when the isocyanate compound, carboxylic anhydride and water react during foaming, the vinyl chloride resin is physically incorporated into the reaction chain, and the obtained foam is a vinyl chloride resin. And the crosslinked polymer chain formed by the reaction of the isocyanate compound, carboxylic anhydride and water are entangled with each other, and a part of the crosslinked polymer chain is graft-bonded to the polymer chain of the vinyl chloride resin. And solvent resistance, heat resistance,
It is considered to be excellent in mechanical strength and the like.

The isocyanate compound generates carbon dioxide gas at the same time as the reaction proceeds, and such carbon dioxide gas can be used as a foaming agent.

Representative examples of the carboxylic acid anhydride include:
Examples thereof 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. These are used in combination.

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 is used. Is preferably 1 part by weight or more, preferably 5 parts by weight or more, based on 100 parts by weight of the vinyl chloride resin, in order to sufficiently reduce the time required for secondary foaming. In order to eliminate the possibility that the cell membrane may be broken due to too high a speed, the content is preferably 100 parts by weight or less, preferably 80 parts by weight or less, more preferably 70 parts by weight or less based on 100 parts by weight of the vinyl chloride resin. .

When the monobasic carboxylic acid anhydride and the dibasic carboxylic acid anhydride are used in combination, the amount of the monobasic carboxylic acid anhydride is, for example, sufficient for the time required for secondary foaming. It is desirable that the amount be 0.5 parts by weight or more, preferably 1 part by weight or more, and more preferably 5 parts by weight or more, based on 100 parts by weight of the vinyl chloride resin. To prevent the cell membrane from being broken by
It is desirably 70 parts by weight or less, preferably 60 parts by weight or less, more preferably 50 parts by weight or less based on 00 parts by weight.

When a monobasic carboxylic anhydride and a dibasic carboxylic anhydride are used in combination, the amount of the dibasic carboxylic anhydride is based on 100 parts by weight of the monobasic carboxylic anhydride. It is preferably at least 50 parts by weight, especially preferably at least 100 parts by weight. In addition, if the compounding amount of the dibasic carboxylic anhydride is too large, the cost increases, so that the monobasic carboxylic anhydride 100
The amount is preferably 1,000 parts by weight or less with respect to parts by weight, and in order to sufficiently exhibit the effect of shortening the time required for secondary foaming, the amount is preferably 500 parts by weight or less.

[0024] The foaming composition generally contains a foaming agent in many cases. The use of such a foaming agent is preferable for increasing the foaming speed, better foaming ratio, and good foaming cells. These foaming agents are 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 blowing 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 and butane, and these foaming agents may be used alone or as a mixture of two or more.

The amount of the blowing agent varies depending on the amounts of the isocyanate compound and the carboxylic anhydride, the desired expansion ratio, the type of the blowing agent, and the like, and cannot be unconditionally determined. The amount of the foaming agent is usually 0.1 part by weight or more, preferably 0.3 part by weight or more based on 100 parts by weight of the vinyl chloride resin in order to impart a desired expansion ratio to the foam. More preferably, the amount is 0.5 part by weight or more. In order to prevent the foamable composition from leaking from the molding die during multi-stage pressing and to prevent the cell membrane from being broken during foaming, the above-mentioned chloride is preferably used. 10 parts by weight or less, preferably 7 parts by weight, based on 100 parts by weight of the vinyl resin.
It is desirable that the amount is not more than 6 parts by weight, more preferably not more than 6 parts by weight.

The foaming agent may be used, if necessary, in combination with a foaming aid such as urea.

If necessary, for example, a stabilizer, an inorganic filler (a bulking 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 impaired.

The stabilizer is not particularly limited as long as it has an ability to prevent decomposition and degradation of the vinyl chloride resin. Specific examples of such stabilizers include, for example, dibasic lead stearate, dibasic lead phosphite, tribasic lead sulfate, zinc stearate, magnesium stearate and the like. These stabilizers may be used alone. Alternatively, two or more kinds are used in combination.

Examples of the inorganic filler include talc, calcium carbonate, shirasu balloon and the like.

The 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 preferable 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 multi-stage hot press of a hydraulic drive type. 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 according to the type and the 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 / c.
m ² · G, preferably 100 to 300 kg / cm ² · G
About G, 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 preferable 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 close to 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 foaming precursor is obtained.

The carboxylic anhydride in the foamable composition does not directly react with the isocyanate compound, but becomes a carboxylic acid in the presence of moisture, and the generated carboxylic acid reacts with the isocyanate compound.

Therefore, the obtained foaming precursor is brought into contact with hot water or high-temperature steam to cause the above-mentioned reaction to proceed, and at the same time, foaming is performed by the generated carbon dioxide gas. In this case,
The temperature of hot water or high-temperature steam is about 80 to 130 ° C., preferably 85 to 110 ° C., and more preferably 90 to 10 ° C. in order to allow the reaction and foaming to proceed sufficiently.
Desirably, the temperature is 0 ° C. When the temperature is lower than 80 ° C., the foam does not foam to a predetermined size, or even if foamed, it takes a long time to foam.
When the value exceeds the above, the cell film tends to be broken. Note that the temperature is desirably 100 ° C. or lower in order to prevent an increase in equipment cost due to the need for special heating equipment.

Thus, the vinyl chloride resin foam of the present invention is obtained.

Since the thickness of the vinyl chloride resin foam varies depending on its use and the like, it cannot be unconditionally determined. When the application is, for example, a core material of a structural panel such as a ship or a pool, the thickness of the vinyl chloride resin foam is set so as to provide mechanical strength and heat insulation required for the structural panel. 1 mm or more, preferably 3 mm
Above, more preferably 5 mm or more, and from the viewpoint of weight reduction and cost, 150 mm or less, preferably 120 mm or less, more preferably 10 mm or less.
It is desirable that it is 0 mm or less.

The shape of the vinyl chloride resin foam is not particularly limited, but is usually a flat plate or a semi-cylindrical shape.

The density of the vinyl chloride resin foam is usually
It is appropriately adjusted depending on the amount of the foaming agent, foaming conditions and the like. The density of the vinyl chloride resin foam is 20 kg / m ³ or more, preferably 25 kg / m ³ or more, more preferably 30 k / m ³ , from the viewpoint of the mechanical strength of the vinyl chloride resin foam.
g / m ³ or more, and 80 kg / m ³ or less, preferably 75 kg / m ³ or less, more preferably 70 kg / m ³ or less from the viewpoint of heat insulation and weight reduction.

The volume retention of the vinyl chloride resin foam of the present invention can be controlled by adjusting the composition of the foamable composition used for the vinyl chloride resin foam plate, as described above, especially by MDI. By using an isocyanate compound composed of the polyisocyanate represented by the general formula (I) in the foamable composition, the content can be adjusted to 80% or more.

The volume retention rate referred to in the present specification is defined as the length of a foam plate having a length of 100 mm × width 100 mm × thickness 10 mm before immersion of the length and thickness, and 80 ° C.
After measuring the size after immersion in the styrene monomer for 1 hour, the formula: [Volume retention (%)] = [Average value of volume before immersion (mm ³ )]
÷ [average value of volume after immersion (mm ³ )] × 100.

The vinyl chloride resin foam of the present invention has a density of 20 to 80 kg / m ³ and has a volume retention of 80% or more after being immersed in a styrene monomer at 80 ° C. for 1 hour. Even if FRP boards are stacked,
It has excellent properties that it does not soften or shrink.

[0048]

EXAMPLES Next, the vinyl chloride resin foam of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Examples 1 to 5 and Comparative Examples 1 to 2 Raw materials were prepared so as to have compositions shown in Table 1, and the total amount was 1 k.
g, and kneaded with a double-arm kneader having an effective volume of 1 liter at room temperature for 45 minutes to obtain a foamable composition.

The obtained foamable composition has an inner size of 155 mm.
It was filled into a molding die made of an aluminum alloy of × 155 mm × 20 mm, set in a press machine, and the molding die was sealed and clamped. Steam is passed through the hot plate of the press, the temperature of the mold is raised to 175 ° C., and the pressure is 210 kg / cm ^2.
After holding at G for 15 minutes, the press hot plate was cooled down to 30 ° C. or less by passing industrial water, the clamping pressure of the press was released, and the molding die was opened to obtain a foam precursor. The dimensions of the obtained foam precursor are 180 mm x 180 mm x 23
mm. Thereafter, the foaming precursor was foamed in hot water at 95 ° C.

Next, the obtained foam was put into industrial water at about 30 ° C., left standing for 30 minutes, cooled, taken out and air-dried to obtain a vinyl chloride resin foam.

Next, a vinyl chloride resin foam was sized to a size of 100 mm using a finishing planarizer and a circular saw.
After finishing to × 100 mm × 10 mm, the density and volume retention of the vinyl chloride resin foam were examined. Table 1 shows the results.
It is described together.

The abbreviations in the table mean the following.

PSH-650A: Paste vinyl chloride resin (manufactured by Kanegafuchi Chemical Industry Co., Ltd., average degree of polymerization: 2400) MDI: polymethylene polyphenyl polyisocyanate TDID: polyisocyanate (n is an average in the general formula (I)) TDI: toluene diisocyanate PP: propionic anhydride PA: phthalic anhydride ACA: azodicarbonamide SL: dibasic lead stearate Next, as physical properties of the obtained polyvinyl chloride resin foam, The state of deformation of the laminate with the FRP plate was examined based on the following method. (Deformation state of laminate with FRP plate) Glass fiber mats on both sides of vinyl chloride resin foam (basis weight 450 g / m ² )
, A gel coat (unsaturated polyester containing 45% by weight of styrene monomer) was applied in an amount of 900 g / m ^2.
And left at 70 ° C. for 24 hours to produce a laminate with the FRP plate.

Next, the state of deformation of the obtained laminate was visually observed. Table 1 shows the observation results.

[0055]

[Table 1] From the results shown in Table 1, the vinyl chloride-based resin foams obtained in Examples 1 to 5 do not undergo softening deformation or shrinkage even when all of them are laminated with the FRP plate. You can see that.

[0056]

The vinyl chloride resin foam of the present invention has an F
Even when laminated with RP board, it may be softened and deformed,
Since it does not shrink, it can be suitably used as a core material of an FRP laminate used for structural panels such as ships and pools.

Claims (2)

[Claims] 1. A vinyl chloride resin, a carboxylic anhydride,
A foam having a density of 20 to 80 kg / m ³ , obtained by foaming a foamable composition containing an isocyanate compound,
A vinyl chloride resin foam having a volume retention of 80% or more after being immersed in a styrene monomer at 0 ° C. for 1 hour. 2. An isocyanate compound comprising polymethylene polyphenyl polyisocyanate and a compound represented by the general formula (I): 2. A polyisocyanate represented by the formula (wherein, n is about 1.4 on average):
The vinyl chloride resin foam according to the above.