JP6506083B2 - Method of manufacturing foamed resin sheet - Google Patents

Description

The present invention relates to a method for producing a foamed resin sheet.

Heretofore, a foam of a resin composition containing a polyolefin resin and a wood-based filler has been used as a cosmetic material because it is excellent in heat insulation and lightweight. However, in order to control foaming and obtain a molded product with high dimensional accuracy, the shape of the molded product is limited, and it is difficult to obtain a foamed resin sheet with high productivity.

Japanese Patent Application Laid-Open No. 10-237206 JP, 2002-361805, A JP 2004-308227 A JP, 2005-307033, A

An object of the present invention is to provide a manufacturing method which can obtain a foamed resin sheet of a resin composition containing a polyolefin resin and a wood-based filler with high productivity.

As a result of earnest studies, the present inventor has found that the above-mentioned problems can be achieved by a specific production method.

That is, the present invention is a method for producing a foamed resin sheet,
(Α) 100 parts by mass of polyethylene resin;
(Β) wood-based filler 5 to 50 parts by mass;
(Γ) inorganic filler 10 to 300 parts by mass; and (δ) foaming agent;
Where the blending amount of the above component (δ) is
Using a foamable resin composition which is 1 to 10 parts by mass with respect to a total of 100 parts by mass of the component (α), the component (β), and the component (γ) And
(1) A step of rolling the foamable resin composition into a sheet using a calender roll set to a temperature exceeding the melting point of the component (α) and a temperature below the decomposition temperature of the component (δ) ;
(2) a step of winding the sheet obtained in the step (1) on a calender roll set to a temperature 25 ° C. or more higher than the decomposition temperature of the component (δ);
(3) a step of winding the sheet treated in the above step (2) on a calender roll set to a temperature not lower than the decomposition temperature of the component (δ) and lower than a temperature 25 ° C. higher than the decomposition temperature;
Method.

A second invention is a foamed resin sheet produced by the method according to the first invention.

According to the production method of the present invention, a foamed resin sheet of a resin composition containing a polyolefin-based resin and a wood-based filler can be obtained with high productivity. The foamed resin sheet obtained by the production method of the present invention can be suitably used for a decorative sheet, a decorative wallpaper, and the like.

The present invention is a method for producing a foamed resin sheet, comprising: (α) 100 parts by mass of a polyethylene resin; (β) 5 to 50 parts by mass of a wood-based filler; (γ) 10 to 300 parts by mass of an inorganic filler; (Δ) a foaming agent; wherein the compounding amount of the component (δ) is 1 to 5 parts by mass with respect to a total of 100 parts by mass of the component (α), the component (β) and the component (γ) The foamable resin composition which is 10 parts by mass is used.

(Α) Polyethylene resin :
The component (α) functions to receive the component (β), the component (γ), and the like and secure sheet productivity.

Examples of the polyethylene resin include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ethylene and α-olefin (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 2-methyl-1-propene, 2-methyl-1-butene, 3-methyl-1-butene, 2-ethyl-1-butene, 2,3-dimethyl- Random copolymer with one or more kinds of 1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene), ethylene-vinyl acetate copolymer, and ethylene-acrylic acid An ester copolymer; and a modified polyethylene obtained by graft polymerizing one or more compounds selected from the group consisting of unsaturated carboxylic acids and derivatives thereof with these. Emissions-based resin; and the like. As said component ((alpha)), 1 type (s) or 2 or more types of mixtures of these can be used.

The melting point of the component (α) is not particularly limited, but may be preferably 110 ° C. or more, more preferably 120 ° C. or more, from the viewpoint of feel and handleability as a foamed resin sheet. From the viewpoint of the productivity of the foamed resin sheet, it may preferably be 135 ° C. or less.

In the present specification, the melting point refers to a differential scanning calorimeter using a Perkin-Elmer Japan Co., Ltd., held at 190 ° C. for 5 minutes, cooled to −10 ° C. at 10 ° C./min, 5 at −10 ° C. The peak top temperature of the peak appearing at the highest temperature side in the second melting curve (melting curve measured in the last heating step) measured by a program held at 10 ° C./min to 190 ° C. Say.

The melt mass flow rate of the component (α) (measured according to JIS K 7210: 1999 and under the conditions of 190 ° C. and 21.18 N) is not particularly limited, but preferably from the viewpoint of the producibility of the foamed resin sheet. It may be 0.1 to 20 g / 10 min, more preferably 0.3 to 10 g / 10 min.

Moreover, in recent years, there are also polyethylene-based resins (hereinafter sometimes abbreviated as biomass polyethylene-based resins) produced using monomers derived from biomass raw materials, and are commercially available. It is also one of the preferred embodiments to use a biomass polyethylene resin as the component (α) so as to be a target of the Biomass Mark of the Japan Organic Resources Association of Japan and the Biomass Mark of the Japan Bioplastics Association.

(Β) wood-based filler :
The component (β) functions to enhance the rigidity of the foamed resin sheet obtained by the production method of the present invention and the machinability at the time of post-processing. It also works to enhance the design.

Examples of the wood-based filler include wood flour and cellulose. As said wood flour, what grind | pulverized wood finely, the sawdust generated at the time of cutting and processing wood, etc. can be mentioned. The above-mentioned cellulose is a polysaccharide in which D-glucose is β-1,4-glucosidically linked, and is usually obtained from cotton, hemp, woody plants and the like, and may be referred to as pulp. As said component ((beta)), 1 type (s) or 2 or more types of mixtures of these can be used.

When the foamed resin sheet obtained by the production method of the present invention requires whiteness, it is preferable to use a high purity chemical pulp as the component (β). When the foamed resin sheet obtained by the production method of the present invention does not require whiteness, it contains a large amount of wood flour and components other than cellulose (such as hemicellulose and lignin) as the component (β) from the viewpoint of cost. It is preferred to use soft pulp, such as mechanical pulp.

From the viewpoint of the feel of the foamed resin sheet obtained by the production method of the present invention, the particle diameter of the component (β) is preferably larger. On the other hand, the smaller one is preferable from the viewpoint of the productivity of the foamed resin sheet. Therefore, the particle size of 90 mass% or more and 40 mesh path of 90 mass% or more of 4000 mesh path is preferable, and the particle size of 90 mass% or more and 50 mesh path of 90 mass% or more of 1000 mesh path is more preferable.

The compounding amount of the component (β) is 5 parts by mass or more, preferably 10 parts by mass or more from the viewpoint of feeling with respect to 100 parts by mass of the component (α). On the other hand, it is 50 parts by mass or less, preferably 30 parts by mass or less from the viewpoint of the productivity of the foamed resin sheet.

(Γ) Inorganic filler:
The component (γ) aids the dispersion of the component (β) in the production (melt-kneading) step of the foamable resin composition used in the production method of the present invention, and a foamed resin sheet obtained by the production method of the present invention Work to make things free of defects.

Examples of the inorganic filler include zeolite, calcium carbonate, bentonite, talc, mica, clay, barium sulfate, natural silicic acid, synthetic silicic acid (white carbon), titanium oxide, carbon black and the like. The use of zeolite as the component (γ) is preferable because the foamed resin sheet obtained by the production method of the present invention can be provided with a humidity control function and a deodorizing function. As said component ((gamma)), 1 type (s) or 2 or more types of mixtures of these can be used.

The average particle diameter of the component (γ) is preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less, from the viewpoint of the productivity of the foamed resin sheet. On the other hand, it is preferably 0.01 μm or more, more preferably 0.02 μm or more, from the viewpoint of assisting the dispersion of the component (β) and preventing the occurrence of defects such as bumps.

In the present specification, the average particle diameter of the component (γ) is a particle diameter distribution curve measured using a laser diffraction / scattering particle size analyzer “MT3200II (trade name)” manufactured by Nikkiso Co., Ltd. Particle size at which 50% by weight of particle size is accumulated.

The compounding amount of the component (γ) is preferably 10 parts by mass or more, from the viewpoint of assisting the dispersion of the component (β) with respect to 100 parts by mass of the component (α) and preventing the occurrence of defects such as bumps. Is 20 parts by mass or more. On the other hand, it is 300 parts by mass or less, preferably 100 parts by mass or less from the viewpoint of the productivity of the foamed resin sheet.

(Δ) blowing agent:
The component (δ) is decomposed and foamed in the step (2), and serves to convert the sheet obtained in the step (1) into a foamed resin sheet.

Examples of the foaming agent include azo compounds such as azodicarbonamide; nitroso compounds such as N, N'-dinitrosopentamethylenetetramine; carbonates such as sodium bicarbonate and ammonium bicarbonate; citric acid, sodium citrate, And organic acids such as boric acid; sodium borohydride; p, p'-oxybisbenzenesulfonyl semicarbazide, p-toluenesulfonyl semicarbazide, compounds such as trihydrazino triazine, and barium azodicarboxylate; and thermally expanded microcapsules etc. You can raise As the above-mentioned foaming agent, for example, the above-mentioned foaming agents such as a combination of a carbonate and an organic acid may be used in combination. As said component ((delta)), 1 type (s) or 2 or more types of mixtures of these can be used.

The decomposition temperature of the component (δ) is preferably higher from the viewpoint of preventing initiation of decomposition / foaming in the step (1). On the other hand, after the above step (3), the lower one is preferable from the viewpoint of enabling release from the calendar roll without trouble. Therefore, although the decomposition temperature of the said component ((delta)) is based also on the resin characteristic of the said foamable resin composition, 145-180 degreeC is preferable normally, and 150-170 degreeC is more preferable.

In the present specification, the decomposition temperature of the blowing agent was measured by the following method. The heat generating decomposition type foaming agent is packed in a capillary in a furnace preheated to a temperature 10 ° C. or more lower than the decomposition temperature using a melting point measuring apparatus “M-560 (trade name)” of Nippon Buchi Co., Ltd. The foaming agent was charged, the temperature was raised at 5 ° C./min, and the temperature at which air bubbles were generated in the tube in the capillary was measured visually. For the endothermic decomposition type foaming agent, use the decomposition behavior measuring device “Gas Tracer (trade name)” manufactured by Eiwa Kasei Kogyo Co., Ltd., add the foaming agent into the test tube and immerse it in the oil bath together with the test tube. Temperature from 100 ° C to 220 ° C at a rate of 2 ° C / min, and measure the integral curve of the amount of gas generation against temperature, and the point before the first inflection point of the integral curve (before gas generation) The temperature at the intersection of a line drawn parallel to the horizontal axis passing through and a tangent drawn so as to maximize the slope between the inflection points of the integral curve (during gas generation) was calculated.

The compounding amount of the component (δ) is 100 parts by mass in total of the component (α), the component (β) and the component (γ) from the viewpoint of the productivity of the foamed resin sheet and the wood texture. 1 to 10 parts by mass, preferably 1.5 to 5 parts by mass.

In the foamable resin composition, the resin other than the component (α); and the filler (for example, resin beads etc.) other than the component (β) and the component (γ) as long as the object of the present invention is not violated Antioxidants such as phenol, phosphorus and sulfur; Antiwetting agents, light stabilizers, and weathering agents such as UV absorbers; Acid amides, fatty acids, fatty acid metal salts, waxes, silicone oils, and modified silicones Lubricants such as oils; Nucleating agents such as metal salts of aromatic phosphates and gelols; Antistatic agents such as glycerin fatty acid esters; Various flame retardants of organic and inorganic types; Coloring agents; Etc. can be further included.

The manufacturing method of the present invention uses a calender roll rolling film-forming apparatus, and (1) a calender roll set to a temperature exceeding the melting point of the component (α) and a temperature lower than the decomposition temperature of the component (δ). And rolling the foamable resin composition into a sheet.

In the step (1), the foamable resin composition is rolled into a sheet. At that time, the temperature (roll surface temperature) of the calender roll in the above step (1) is the above component (the roll surface temperature) in order to prevent decomposition and foaming of the above component (δ) from starting and stably performing the above step (1). The temperature is set lower than the decomposition temperature of δ), preferably 2 ° C. or more lower than the decomposition temperature of the component (δ), more preferably 5 ° C. or more lower than the decomposition temperature of the component (δ). From the viewpoint of preventing initiation of decomposition / foaming of the component (δ) in the step (1), the lower the temperature of the calender roll, the more preferable. On the other hand, from the viewpoint of sufficiently plasticizing the component (α) and improving the surface condition of the obtained sheet, the temperature of the calender roll is a temperature exceeding the melting point of the component (α), preferably the component (α) It is set to a temperature 5 ° C. or more higher than the melting point of the above, more preferably 10 ° C. or more higher than the melting point of the component (α).

Before the step (1), the foamable resin composition has a temperature exceeding the melting point of the component (α), preferably a temperature higher by 5 ° C. or more than the melting point of the component (α), more preferably the component A temperature higher by 10 ° C. or more than the melting point of (α) and a temperature lower than the decomposition temperature of the component (δ), preferably a temperature lower by 2 ° C. or more than the decomposition temperature of the component (δ), more preferably the component (6) It is preferable to be preheated to a temperature 5 ° C. or more lower than the decomposition temperature of δ). Sheeting in the step (1) is facilitated.

The method of the preheating is not particularly limited, and may be performed by any method. For example, an extruder such as a planetary multi-screw extruder, a co-rotating twin screw extruder, a co-rotating twin screw extruder, and a single-screw extruder; a batch kneader such as a pressure kneader and a mixer; mixing such as two rolls By using a roll, a combination thereof or the like, the foamable resin composition preheated by melt-kneading the foamable resin composition into a strand, a sheet, a rod, a scrap, a small lump, etc. The way to get in the state of

The production method of the present invention comprises (2) a step of winding the sheet obtained in the above step (1) on a calender roll set at a temperature 25 ° C. or more higher than the decomposition temperature of the component (δ). .

The sheet obtained in the step (1) is wound on a calender roll set at a temperature 25 ° C. or more higher than the decomposition temperature of the component (δ) in the step (2), whereby the sheet in the sheet is The component (δ) is decomposed and foamed to form a foamed resin sheet.

By foaming while being wound on a calender roll, the foam cells become elongated spindle / conduit shape in the machine direction. Therefore, the foamed resin sheet obtained by the production method of the present invention can be suitably used as a decorative sheet for giving a wood-like design.

The temperature (roll surface temperature) of the calender roll in the step (2) is 25 ° C. higher than the decomposition temperature of the component (δ) so that the decomposition and foaming of the component (δ) occur rapidly and completely. It is set to a temperature higher by ° C. or higher, preferably 30 ° C. or higher than the decomposition temperature of the component (δ). On the other hand, from the viewpoint of preventing the deterioration of the components (α) to (γ), the temperature of the calender roll may be preferably 220 ° C. or less, more preferably 200 ° C. or less.

The production method of the present invention comprises (3) a calender roll set to a temperature above the decomposition temperature of the component (δ) and a temperature below 25 ° C. higher than the decomposition temperature of the sheet treated in the step (2). Including the step of winding.

The sheet foamed in the step (2) is cooled to a temperature above the decomposition temperature of the component (δ) and at a temperature 25 ° C. higher than the decomposition temperature in the step (3), The calendar roll can be released and sent to the next process without causing problems such as adhesion to the guide roll. In addition, since the temperature is maintained at a temperature higher than the decomposition temperature of the component (δ), the component (δ) remaining without being decomposed and foamed in the step (2) is decomposed and foamed so that it does not remain Can be

The temperature of the calender roll (roll surface temperature) in the step (3) is the temperature of the component (.delta.) From the viewpoint of completely decomposing and foaming the component (.delta.) In the step (3) so as not to remain. It is set to a temperature higher than the decomposition temperature, preferably 10 ° C. or more higher than the decomposition temperature of the component (δ), more preferably 15 ° C. or more higher than the decomposition temperature of the component (δ). On the other hand, the temperature of the calender roll is preferably less than 25 ° C. higher than the decomposition temperature of the component (δ), preferably, from the viewpoint of enabling the sheet to be sent to the next step without causing troubles. The temperature is set to 20 ° C. higher than the decomposition temperature of the component (δ) or lower. It is more preferable that the temperature of the calender roll in the above step (3) is 180 ° C. or less, because the release property from the calender roll becomes very good.

As the calender roll rolling film-forming apparatus, the number of calender rolls used in the step (1) is two or more for forming a rolled sheet, and the number of calender rolls used in the step (2) is one or more And the number of calender rolls used in the above step (3) is not particularly limited, and any device can be used. For example, 2 rolls, upright 3 rolls, upright 4 rolls, L-shaped 4 rolls, inverted L-shaped 4 rolls, Z-shaped rolls, L-shaped 6 rolls, inverted L-shaped 6 rolls, and these Combinations of

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

Measurement method (a) Expansion ratio:
The specific gravity (g1) of the foam sheet was determined from the volume and the mass of the foam resin sheet. Next, a resin composition containing no foaming agent (in the case of Example 1, 100 parts by mass of (α-1), 20 parts by mass of (β-1), 40 parts by mass of (γ-1), and (γ) -2) For a resin sheet obtained in the same manner as the foamed resin sheet except that a resin composition containing 10 parts by mass and 10 parts by mass of (.epsilon.-1) is used, from the volume and the mass , Its specific gravity (g2) was determined. The foaming ratio (h) was calculated by the following equation.
h = g2 / g1

(B) Heat transfer rate:
Using KOTO TEC's finger robot contact cooling / heating sensation measuring device “KES-F7 (trade name)”, heat transfer speed Qmax of the foamed resin sheet at an outside air temperature of 23 ° C. and a sensor block temperature of 33 ° C. The value obtained by multiplying the maximum value of seconds by 0.1) was measured.

Raw materials used (α) Polyethylene resin:
(Α-1) Biomass polyethylene resin “SGE 7252 (trade name)” manufactured by Blaschem, density 953 Kg / m ³ , MFR 2.2 g / 10 min, melting point 130 ° C.
(Α-2) Biomass polyethylene resin “SLL 918 (trade name)” manufactured by Blaschem, density 918 Kg / m ³ , MFR 2.7 g / 10 min, melting point 124 ° C.

(Β) wood-based filler:
(Β-1) Wood flour, particle size 300 mesh pass 90% by mass or more, average particle diameter 60 μm.
(Β-2) High Purity Chemical Pulp “KC Flock W-400G (trade name)” manufactured by Nippon Paper Industries Co., Ltd., Particle size 400 mesh pass 90 mass% or more, average particle diameter 24 μm.

(Γ) Inorganic filler:
(Γ-1) Zeolite "SGW (trade name)" of Zekrite Co., Ltd., average particle diameter 10 μm.
(Γ-2) Titanium dioxide “R-11P (trade name)” manufactured by Sakai Chemical Industry Co., Ltd., average particle diameter 0.20 μm.
(Γ-3) Calcium carbonate “Vigot 10 (trade name)” manufactured by Shiroishi Kogyo Co., Ltd., average particle diameter 0.1 μm.

(Δ) blowing agent:
(Δ-1) Sodium bicarbonate complex composite foaming agent “Cerbon SC-53 (trade name)” manufactured by Eiwa Chemical Co., Ltd., decomposition temperature 150 ° C. Endothermic decomposition type.
(Δ-2) Azodicarbonamide-based composite foaming agent “Biniphor DW # 6 (trade name)” manufactured by Eiwa Kasei Kogyo Co., Ltd., decomposition temperature 165 ° C. Heat decomposition type.

(Ε) Arbitrary component:
(Ε-1) Zinc stearate.

Example 1
100 parts by mass of (α-1), 20 parts by mass of (β-1), 40 parts by mass of (γ-1), 10 parts by mass of (γ-2), 5 parts by mass of (δ-1) 2.9 parts by mass with respect to a total of 100 parts by mass of the above (α-1), the above (β-1), the above (γ-1), and the above (γ-2), and the above (ε-1) 2.) A foamable resin composition containing 10 parts by mass is melt-kneaded using a mixer under the conditions of a resin temperature of 140 ° C. at discharge and further melted using a two-roll type mixing roll set at a temperature of 145 ° C. After kneading, the mixture was immediately loaded into a L-type 4-roll type calender roll rolling film-forming apparatus. The first two calender rolls of the device are preset to a temperature of 145 ° C. The foamable resin composition is rolled using the first two calender rolls, sent to a calender roll previously set to a temperature of 185 ° C., wound around it, and allowed to foam, and then the temperature is further preliminarily raised. The sheet was sent to a calender roll set at 165 ° C. and wound around it, and then the sheet was wound up to obtain a foamed resin sheet with a thickness of 300 μm. The above tests (a) and (b) were performed. The results are shown in Table 1.

Examples 2-15, Examples 1C-6C
The same procedure as Example 1 was followed except that at least any one of the production conditions of the foamed resin sheet and the composition of the foamed resin composition was changed as shown in any one of Tables 1 to 3. The results are shown in any one of Tables 1 to 3.

According to the production method of the present invention, a foamed resin sheet of a resin composition containing a polyolefin-based resin and a wood-based filler can be obtained with high productivity. Moreover, since the obtained foamed resin sheet has a high foaming ratio and a small heat transfer rate, it can be used to obtain a decorative sheet with high wood texture, decorative wallpaper, and the like. On the other hand, in Examples 1C and 3C to 6C, the expansion ratio of the obtained foamed resin sheet was low, and the heat transfer rate was large. In Example 2C, it was not possible to form a rolled sheet in step (1). Therefore, step (2) and subsequent steps could not be performed.

It is a conceptual diagram which shows an example of the manufacturing method of this invention.

1: Foamable resin composition 2: Sheet before foaming 3: Foamed resin sheet 4: First two calender rolls 5 used in step (1) Calender roll used in step (2) 6: Step (3) Calendar roll used in)

Claims (6)

A method for producing a foamed resin sheet, comprising
(Α) 100 parts by mass of polyethylene resin;
(Β) wood-based filler 5 to 50 parts by mass;
(Γ) inorganic filler 10 to 300 parts by mass; and (δ) foaming agent;
Where the blending amount of the above component (δ) is
Using a foamable resin composition that is 1 to 10 parts by mass with respect to a total of 100 parts by mass of the above component (α), the above component (β), and the above component (γ)
Use calendar roll rolling film making equipment,
(1) A step of rolling the foamable resin composition into a sheet using a calender roll set to a temperature exceeding the melting point of the component (α) and a temperature below the decomposition temperature of the component (δ) ;
(2) a step of winding the sheet obtained in the step (1) on a calender roll set to a temperature 25 ° C. or more higher than the decomposition temperature of the component (δ);
(3) a step of winding the sheet treated in the above step (2) on a calender roll set to a temperature not lower than the decomposition temperature of the component (δ) and lower than a temperature 25 ° C. higher than the decomposition temperature;
Method including.
The method according to claim 1, wherein the decomposition temperature of the component (δ) is 145 to 180 ° C.
The method according to claim 1 or 2, wherein the component (γ) comprises a zeolite.
The method according to any one of claims 1 to 3, wherein the component (α) contains a biomass polyethylene resin.
It is a manufacturing method of a makeup sheet,
A step of producing a foamed resin sheet by the method according to any one of claims 1 to 4;
Method including.
It is a manufacturing method of makeup wallpaper,
A step of producing a foamed resin sheet by the method according to any one of claims 1 to 4;
Method including.