JPH0730198B2 - Expandable vinyl chloride resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a foamable vinyl chloride resin composition.

[0002]

2. Description of the Related Art Generally, a vinyl chloride resin foam is relatively inexpensive, has excellent flame retardancy, low moisture absorption and surface smoothness, and is lightweight. Sheets are widely used, for example, as advertising billboards, display boards, and wall materials for exhibition booths.

Conventionally, foamable vinyl chloride resin compositions for forming sheets of vinyl chloride resin foam have been
A heat stabilizer is blended, and as such a stabilizer,
Conventionally, a cadmium-barium stabilizer and a lead stabilizer have been used.

[0004]

However, conventional cadmium-barium stabilizers and lead stabilizers are
Although it has excellent thermal stability, it is highly toxic, and there is a strong risk that it will be harmful to the health of the workers who handle it.
Also, choking (powdering phenomenon) on the surface of the molded sheet
Since it is apt to occur, it is not suitable for long-term outdoor use, and there is a problem that it is difficult to use it for the above-mentioned advertising signboard and the like.

In order to solve such a problem, it has been previously proposed to use a stabilizer composed of dibutyltin maleate, which has low toxicity, alone (for example, JP-A-53-642).
No. 76).

However, when the previously proposed dibutyltin maleate is used alone, since the foamable vinyl chloride resin composition has less slipperiness, that is, slipperiness in the extruder and the die, the kneading in the extruder is difficult. There has been a problem that (kneading) becomes excessive, the pores (cells) of the formed vinyl chloride resin foam become non-uniform, and the surface condition is not smooth.

Therefore, when the stabilizer made of dibutyltin maleate was added excessively, the surface condition and the uniformity of the pore diameter were improved, but the stabilizer plate out (bleeding) occurred. If such a plate-out occurs, the printing (printing) of the ink or paint on the foam is hindered, and the printability deteriorates. Therefore, when it is used as a signboard or a display board, there is a problem that it is very inconvenient. It was

The inventors of the present invention have conducted extensive studies in view of the above points, and as a result, by adding a predetermined amount of two low-toxic stabilizers of dibutyltin maleate and dioctyltin maleate to vinyl chloride resin, The present invention has been completed by finding out that the above-mentioned problems of the prior art are solved.

The object of the present invention is that the surface condition is smooth, discoloration or burning does not occur, the pore size is uniform, and the foaming condition is good, and the dispersibility of the pores is excellent. A vinyl chloride resin foam that does not cause plate-out is obtained, and since it has low toxicity, there is no problem with hygiene such as work environment hygiene, and it does not harm the health of workers. To try to deliver things.

[0010]

In order to achieve the above object, the present invention provides 100 parts by weight of vinyl chloride resin, 1.0 to 3.0 parts by weight of dibutyltin maleate and dioctyltin maleate. 1.0 to 2.0 parts by weight, 0.1 to 1.0 parts by weight of a chemical foaming agent, and 1.0 to 25.0 parts by weight of an acrylic processing aid are blended. The subject is a foamable vinyl chloride resin composition.

In the above, as the vinyl chloride resin,
A single polymer having an average degree of polymerization of about 700 to 1300 is preferably used.

The amount of dibutyltin maleate added is 1.0 to 3.0 with respect to 100 parts by weight of the vinyl chloride resin.
Parts by weight. Here, if the addition amount of dibutyltin maleate is less than 1.0 part by weight, thermal stability is not sufficient, so burning occurs, the surface is not smooth, and the surface condition is significantly impaired, which is not preferable. On the other hand, when the amount of dibutyltin maleate added exceeds 3.0 parts by weight, a heat stabilizing effect can be expected, but plate out occurs.
A particularly suitable amount of addition is 1.5 to 2.5 parts by weight.

The amount of octyl tin maleate added is 1.0 to 2.0 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount added is less than 1.0 part by weight, a sufficient lubrication effect cannot be obtained, and over-foaming occurs, so that a good surface condition and pores having a uniform diameter cannot be obtained. On the other hand, when the amount exceeds 2.0 parts by weight, plate-out is large, and the foaming property is impaired due to excessive lubricity, resulting in under-foaming. A particularly suitable amount of addition is 1.2 to 1.7 parts by weight.

As the chemical foaming agent, for example, the decomposition temperature is 1.
Organic blowing agents such as azo compounds, azide compounds, nitroso compounds, and sulfohydrazide compounds that explosively decompose at about 30 to 150 ° C. are preferable. Especially, azodicarbonamide (ADCA) whose decomposition temperature was lowered by addition of urea
Is preferably used. The addition amount is usually 0.1 to 1.0 parts by weight with respect to 100 parts by weight of vinyl chloride resin,
It is used within this range depending on the expansion ratio, but a particularly suitable amount is 0.2 to 0.3 part by weight.

Further, the addition amount of the acrylic processing aid is
1.0-2 for 100 parts by weight of vinyl chloride resin
5.0 parts by weight, but a particularly suitable amount is 10.0
~ 20.0 parts by weight.

Specific examples of the acrylic processing aid include methylmethacrylate, ethylmethacrylate, or butylmethacrylate homopolymer, or copolymers of these alkylmethacrylates, or methylmethacrylate or ethylmethacrylate. , Or an alkyl methacrylate composed of butyl methacrylate, which is copolymerized with an alkyl acrylate such as methyl acrylate, ethyl acrylate, and butyl acrylate, and the above alkyl methacrylate, styrene, α-methylstyrene, vinyl aromatic such as vinyltoluene. Compound, or acrylonitrile,
Examples thereof include those obtained by copolymerizing vinyl cyanide compounds such as methacrylonitrile.

These acrylic processing aids can be used alone or in combination. The addition amount is 1 to 25 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.
20 parts by weight is preferred. If the amount of the acrylic processing aid added is less than 1 part by weight, the gelation is insufficient, so that the burning,
Ripples are generated, and a good surface condition cannot be obtained for the foam sheet. On the other hand, if it exceeds 25 parts by weight, the amount is too large and plate-out is likely to occur, which is not preferable.

The expandable vinyl chloride resin composition according to the present invention generally contains, in addition to the above-mentioned constituents of dibutyl tin maleate, dioctyl tin maleate, a chemical foaming agent, and an acrylic processing aid, a chloride. Other additives used for vinyl resins, namely lubricants,
There is no problem in adding an impact modifier, a coloring agent such as a white pigment typified by titanium oxide, and a trace amount of an ultraviolet absorber.

[0019]

The above-mentioned resin composition of the present invention comprises a vinyl chloride resin and a predetermined amount of two kinds of stabilizers, dibutyltin maleate and dioctyltin maleate, blended therein so that the surface condition is smooth, and discoloration or burning does not occur. It is possible to obtain a vinyl chloride resin foam which does not occur, has a uniform size of pores, has a good foaming state, has excellent dispersibility of pores, and does not cause plate-out. Further, since the two types of stabilizers, dibutyltin maleate and dioctyltin maleate, both have low toxicity, there is no problem in hygiene such as working environment hygiene, and the health of workers is not impaired.

[0020]

Embodiments of the present invention will be described below.

Examples 1 to 4 First, a vinyl chloride resin having an average degree of polymerization of 800 (trade name, Kanevinyl S-1008, manufactured by Kanebuchi Chemical Industry Co., Ltd.) 1
To 100 parts by weight of dibutyl tin maleate (trade name, Stan BM-N, manufactured by Sansha Machine Synthetic Co., Ltd.) and dioctyl tin maleate (trade name, Stan OM, Sansha Machine Synthesizer Co., Ltd.) in an amount of 100 parts by weight, respectively. Two types of stabilizers consisting of a chemical foaming agent (trade name, Celmic CAP)
-250, azodicarbonamide (ADCA), manufactured by Sankyo Kasei Co., Ltd., and acrylic processing aid (trade name,
METABLEN P-530A, manufactured by Mitsubishi Rayon Co., Ltd.) was blended with the expandable vinyl chloride resin composition of the present invention, and this was mixed for 10 minutes with a high speed mixer,
At the same time, it was heated to 105 ° C. Next, this expandable vinyl chloride resin composition was introduced into an extruder, and the composition was kneaded while being extruded by a screw in a cylinder,
Raise the temperature to 50 ° C. Then, this kneaded product is passed through an adapter and a die of an extruder to obtain a thickness of 5 mm by an extrusion method.
Was molded into a vinyl chloride resin foam sheet.

Comparative Examples 1 to 8 For comparison, the same vinyl chloride resin as above was used.
0 parts by weight, 0.2 parts by weight of the chemical foaming agent, and 15.0 parts by weight of the acrylic processing aid were fixed, and dibutyltin maleate was added outside the range of the composition of the present invention ( Comparative Examples 1, 2, 4, 6) and dioctyl tin maleate outside the range of the composition of the present invention (Comparative Examples 1, 2, 3, 5, 7) were prepared in the same manner. Similarly, a vinyl chloride resin foam sheet was formed from the product by an extrusion method.

Further, only the amount of the acrylic processing aid compounded is set to 0, and other vinyl chloride resin, dibutyltin maleate, acrylic processing aid, and chemical foaming agent are within the range of the composition of the present invention ( Comparative Example 8) was prepared in the same manner, and a vinyl chloride resin foam sheet was also formed from this.

With respect to the vinyl chloride resin foam sheets of Examples 1 to 4 and Comparative Examples 1 to 8 obtained as described above, the surface condition, the uniformity of pore diameter, the foamed condition,
Various characteristics of occurrence of plate-out were measured, and the obtained results are summarized in Table 1.

The evaluation method of each characteristic is as follows.

(1) Surface condition: The vinyl chloride resin foam sheet obtained by the extrusion method has a smooth surface, no waviness (dents), or no burning or discoloration. And On the other hand, when the surface had corrugations (hollows) or burned or discolored, x was marked as bad, and it was described whether corrugation or burnt occurred.

(2) Uniformity of Pore Diameter A vinyl chloride resin foam sheet is placed in a plane perpendicular to the extrusion direction.
Cut and observe this cross section with an 80x stereo microscope,
The diameter of the pores in the center of the sheet and near the surface layer was observed to determine the uniformity. Those having uniform pore diameters in these portions were evaluated as good, and those having irregular pore diameters, such as the presence of abnormally large pores in the central portion of the sheet, were rated as x.

(3) Foamed state It is judged whether or not the dispersed state (formed state) of the pores of the vinyl chloride resin foam sheet is uniform.
Since it appears in the apparent density (g / cm ³ ) of the foam sheet, the apparent density of the sheet was measured and the specific numerical value was entered. Here, the apparent density is 0.70
It can be said that the dispersion state (formation state) of the pores is uniform in the range of 0.79 g / cm ³ .

(4) Presence or absence of plate-out The presence or absence of plate-out can be measured by directly observing the surface of the vinyl chloride resin foam sheet after extrusion. When the plate is out (bleeding out), it appears as a stain on the surface of the polishing roll arranged immediately after the extruder. Therefore, here, the foam sheet was continuously extruded for 4 hours. After that, it was judged by observing stains on the surface of the polishing roll, and described as the presence or absence of occurrence of plate-out.

[0030]

[Table 1]

As is clear from the results shown in Table 1 above, the vinyl chloride resin foam sheets according to Examples 1 to 4 of the present invention have a good surface condition and very high pore uniformity. It was confirmed that the state of dispersion of pores due to foaming was extremely good, and that plate-out did not occur, which was much better in the comprehensive evaluation.

On the other hand, the vinyl chloride resin foam sheets of Comparative Examples 1 to 8 in which one or both of dibutyltin maleate and dioctyltin maleate are not blended are suitable for the surface state and the pores. Once, no favorable result was obtained in evaluation of the dispersed state (apparent density) of pores due to foaming and the presence or absence of plate-out, and it was unusable, for example, as an advertising signboard and a display board.

[0033]

As described above, the foamable vinyl chloride resin composition according to the present invention contains 100 parts by weight of the vinyl chloride resin and 1.0 to 3.0 parts by weight of dibutyltin maleate.
And 1.0 to 2.0 parts by weight of dioctyl tin maleate, 0.1 to 1.0 parts by weight of a chemical foaming agent, and 1.0 to 25.0 parts by weight of an acrylic processing aid. According to the composition of the present invention, the surface state is smooth, discoloration or burning does not occur, and the size of the pores is uniform, and the foaming state is good, and the dispersibility of the pores is improved. It is possible to obtain a vinyl chloride resin foam which is excellent and does not cause plate-out. In addition, since the two types of stabilizers, dibutyltin maleate and dioctyltin maleate, are both low-toxic, there are no problems in hygiene such as work environment hygiene, and the health of workers is not impaired.
It has the effect of being able to prevent illness.

Claims (1)

[Claims] 1. A vinyl chloride resin of 100 parts by weight, dibutyltin maleate of 1.0 to 3.0 parts by weight and dioctyltin maleate of 1.0 to 2.0 parts by weight, and a chemical foaming agent of 0.1. ˜1.0 parts by weight and an acrylic processing aid 1.0 to 25.0 parts by weight are blended, and a foamable vinyl chloride resin composition.