JP2002348396A - Thermoplastic resin foam and production method for thermoplastic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin foam which is a low-density one harmless to a human body, is excellent in recyclability and in capability for scavenging formaldehyde, ammonia, etc., and can be used as a building material or a furniture material; and a production method for the foam. SOLUTION: This thermoplastic resin foam is prepared from a polystyrene resin or a polyolefin resin, has an open cell content of 5% or higher, and contains 0.01-20 wt.% polyphenol compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin foam having formaldehyde-capturing ability, ammonia-capturing ability and the like, and a method for producing the foam.

[0002]

2. Description of the Related Art In recent years, as houses become more airtight and heat insulating, indoor air pollution by various volatile gases has become an important problem. One of such volatile gases is formaldehyde, which is said to be released into the room from building materials, building interior materials, furniture and the like, irritating eyes, nose, throat, etc., and causing allergies. In view of such circumstances, measures have to be taken to absorb and remove formaldehyde released into the room, and regulation standards for formaldehyde concentration in homes have been set.

On the other hand, it is known that polyphenol compounds derived from plants have high reactivity with formaldehyde, are harmless to human bodies in many cases, and are not volatile, so there is no risk of causing secondary pollution. In addition, a sheet or the like provided with formaldehyde trapping ability or the like by containing the polyphenol compound has been proposed.

For example, Japanese Patent Application Laid-Open No. 6-122746 describes that a foam is produced by adding catechin which is a vegetable polyphenol to urethane foam. However, since urethane foam cannot be recycled, there is a problem in effective use of resources.

[0005] Japanese Patent Application Laid-Open No. 11-226100 discloses that a plant polyphenol is contained in a raw material, or is directly impregnated, coated, or sprayed to form a sheet-forming material, a building material such as a wood material, a furniture material, or a filter. And the like.

[0006] Japanese Patent Application Laid-Open No. 2000-177035 describes a decorative sheet comprising a base layer and a foamed layer containing vegetable tannins (polyphenols). Japanese Patent Application Laid-Open No. 2000-177035 describes a decorative sheet comprising a base layer, a foam layer, and a protective layer containing vegetable tannins (polyphenols).

[0007] However, these sheets are difficult to recycle, and the problem remains in that inexpensive products are manufactured because of the multiple manufacturing steps. In the latter, since the foamed layer is formed using a thermal expansion type capsule foaming agent containing a volatile substance or the like or a chemical foaming agent, only a high-density foam can be obtained. For this reason, the properties of the foam cannot be sufficiently exhibited, and its use is limited.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is a low-density foam which is harmless to the human body, has excellent recyclability, and is superior in formability and ammonia to conventional ones. It is an object of the present invention to provide a thermoplastic resin foam excellent in the ability to capture odors and usable as a building material or a furniture material, and a method for producing the foam.

[0009]

The present invention provides (1) a foam comprising a polystyrene-based resin or a polyolefin-based resin, which has an open cell ratio of 5% or more and a polyphenol compound content of 0.01 to 20% by weight. % (2) a thickness of 0.
The thermoplastic resin foam according to the above (1), wherein the thermoplastic resin foam has a thickness of 5 to 10 mm, an average cell diameter of 0.3 to 2 mm, and an apparent density of 15 to 75 kg / m ^3.
70. The thermoplastic resin foam according to (1), wherein the average cell diameter is 0.2 to 5 mm, the apparent density is 22 to 100 kg / m ³ , and the area of the cross section perpendicular to the longitudinal direction is 25 cm ² or more. (4) The thermoplastic resin foam according to any of (1) to (3) above, wherein the polyphenol compound is a compound represented by the following general formula (I):

Embedded image (However, in the formula (I), R1, R2, and R3 each represent any one of a hydrogen atom and a hydroxyl group, and R4 represents any one of a hydrogen atom and a galoilo group represented by the following general formula (II).)

Embedded image (5) The polyolefin resin foam according to any one of (1) to (4), wherein a deodorant is added, and (6) the deodorant contains a silicon compound having deodorant properties. (7) The polyolefin resin foam according to the above (5), (7) the polyolefin resin foam according to the above (6), wherein the deodorizing silicon compound is hydrated silica. A foamable molten resin composition comprising a polystyrene resin having a melt flow rate of 0.5 to 35 g / 10 min and a polyphenol compound in an amount of 0.01 to 20% by weight and a physical foaming agent is subjected to high-pressure molding using an extruder. (9) a melt flow rate of 0.3 to 15 g / 10 minutes, and a melt tension of 4 to 30 g, wherein a thermoplastic resin foam is extruded and foamed from a pressure range to a low pressure range.
(f) extruding a foamable molten resin composition in which 0.01 to 20% by weight of a polyphenol compound and a physical foaming agent are added to a polypropylene resin from a high-pressure region to a low-pressure region using an extruder; The method for producing a thermoplastic resin foam, wherein (10) the melt flow rate is 0.1 to
30 g / 10 min, a polyphenol compound having a density of 940 kg / m ³ or less and a polyphenol compound of 0.01 to 20
A method for producing a thermoplastic resin foam, comprising: extruding a foamable molten resin composition having a weight percent and a physical foaming agent added thereto from a high pressure range to a low pressure range using an extruder;
(11) The thermoplastic resin foam according to any one of (8) to (10), wherein the extrusion conditions are adjusted such that the maximum temperature of the molten resin in the extrusion foaming step is 220 ° C. or less. The gist is the manufacturing method of

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A thermoplastic resin foam (hereinafter referred to as a foam) of the present invention comprises a polystyrene resin or a polyolefin resin. A polystyrene resin is easily foamed and has excellent mechanical strength, so that a foam excellent as a building material having low density and excellent heat insulation can be obtained. In addition, polyolefin-based resins are rich in flexibility and excellent in chemical resistance, so that a foam excellent as a material for construction or furniture can be obtained.

The polystyrene resin is mainly composed of styrene homopolymer or styrene (50% by weight or more).
A styrene-based copolymer or a mixture thereof, or one or more selected from the group consisting of the styrene homopolymer and the styrene-based copolymer as a main component (50% by weight).
And mixed resins obtained by mixing other thermoplastic resins and rubber components as auxiliary components. Examples of the polystyrene copolymer include styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-butadiene copolymer, and styrene- Butadiene-acrylonitrile copolymer and the like.
In addition, as the resin or rubber mixed as the sub-component,
Examples include polyphenylene oxide, butadiene rubber, butadiene-styrene copolymer rubber, styrene-ethylene copolymer, and styrene elastomer.

As the polyolefin resin, one or more selected from the group consisting of a polyethylene resin or a polypropylene resin or a mixture thereof, or the polyethylene resin and the polypropylene resin are used as main components (50% by weight). And mixed resins obtained by mixing other thermoplastic resins and rubber components as auxiliary components. Examples of the polyethylene resin include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate Copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene- A methacrylic acid copolymer, an ethylene-styrene copolymer and the like are included, and a low-density polyethylene is preferred from the viewpoint of proper extrusion foaming.

The above-mentioned polypropylene resin includes, for example,
A propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene copolymer, a propylene-ethylene-butene copolymer, and the like are included, and a polypropylene resin having a long chain branch is preferable from the viewpoint of extrusion foaming suitability.

The foam of the present invention has an open cell ratio of 5% or more,
It is preferably at least 10%, more preferably at least 50%. When the open cell ratio is 5% or more, the foam film of the open cell structure portion formed on the outside and inside of the foam comes into direct contact with formaldehyde and the like, so that formaldehyde and the like are also trapped inside the foam. Therefore, it has a much better ability to trap formaldehyde and the like as compared to non-foamed and closed-cell foams.

That is, the excellent ability to trap formaldehyde and the like is due to the increase in the adsorption efficiency due to the increase in the surface area of the foam as the adsorbent, the chemical adsorption ability by the polyphenol compound, and the above-mentioned chemical adsorption ability. It is considered that the sustainability of the trapping ability and the effect of suppressing the release of adsorbed substances into the atmosphere by the complicated intricate air passage formed by the open cell structure of the foam are exhibited together.

In order to obtain a foam having an open cell ratio in the above range, for example, a method of using a mixture of two or more resins having different melt flow rates as a base resin of the foam, a viscoelastic property upon melting And a method using two or more resin mixtures different from each other. Specifically, a resin mixture of low-density polyethylene and ethylene-methyl methacrylate copolymer or a resin mixture of low-density polyethylene, high-density polyethylene and ethylene-ethyl acrylate copolymer is used as a base resin and extrusion foaming is performed. By adjusting the temperature, it is possible to obtain a foam having an open cell structure with good appearance without shrinkage.

Further, even if the foam has a closed cell structure,
Using the through-hole forming apparatus 1 shown in FIG. 1, a needle roll 2 provided with a through-hole forming needle 4 and a receiving roll 3 are used.
While rotating the needle roll 2 and the receiving roll 3, the foam 5
Is passed through the gap between the needle roll 2 and the receiving roll 3 to form a foam 6 having an open-cell structure in which a through-hole 7 is formed. However, when the foam having the closed-cell structure is made to have the open-cell structure by the processing method using the needle roll, the air passage formed in the foam becomes only the needle hole portion and becomes a linear air passage. It is considered that the release suppressing effect is somewhat inferior to that based on a foam having an open-cell structure. This processing method using a needle roll can also be used to further improve the open cell ratio of a foam having an open cell structure.

In the present specification, the measurement of the open cell ratio is as follows.
This is performed as follows according to STM D-2856-70 [1976 recertification] (procedure C). The true volume Vx (cm ³ ) of the measurement sample was determined using an air pycnometer, the apparent volume Va (cm ³ ) was determined from the outer dimensions of the measurement sample, and the open cell ratio (%) was calculated according to equation (1). calculate. The true volume Vx is the sum of the volume of the resin in the measurement sample and the volume of the closed cell portion.

[0019]

## EQU1 ## In the equation (1), W is the weight (g) of the measurement sample, and ρ is the open cell ratio (%) = {(Va−Vx) / (Va−W / ρ)} × 100. It is the density (g / cm ³ ) of the substrate constituting the foam.

When the foam is in the form of a sheet,
Cut out a plurality of 40 mm long, 25 mm wide sheet-shaped samples, and overlap the cut-out samples to obtain a thickness of about 25 m.
m is used. The test pieces were stacked so that there was as little gap between the test pieces as possible and about 25 mm
Thickness. If the foam is plate-shaped or long, the length is 40
A piece cut out to a size of 25 mm, a width of 25 mm and a thickness of 25 mm is used as a test piece. If a test piece of the above size cannot be cut out of the foam, a plurality of samples as large as possible are cut out and combined to obtain a 40 m long.
m, 25 mm in width and 25 mm in thickness.

The apparent density of the foam of the present invention is 15 to 40.
0 kg / m ³ is preferred. An apparent density of 15 kg / ^{m 3}
If it is less than 1, the expansion ratio is too large, and the mechanical strength of the foam may be reduced. Further, since the content of the polyphenol compound per volume of the foam decreases, there is a possibility that the formaldehyde trapping ability and the like may decrease. On the other hand, when the apparent density exceeds 400 kg / m ³ , the foaming ratio is too small to obtain a sufficient contact area, and there is a possibility that the formaldehyde capturing ability or the like does not increase.

The foam of the present invention contains 0.01 to 20% by weight of a polyphenol compound. When the addition amount of the polyphenol compound is less than 0.01% by weight, there is a possibility that sufficient formaldehyde trapping ability or the like cannot be obtained. When the addition amount of the polyphenol compound exceeds 20% by weight, it is difficult to obtain a foam, and it may not be possible to obtain an effect commensurate with the content, resulting in an increase in cost. The foam of the present invention is preferably added with a polyphenol compound in an amount of 0.1 to 10% by weight, from the viewpoint that the formaldehyde scavenging ability and the like are excellent and a high-quality foam can be obtained. More preferably, it is added by weight%.

The polyphenol compound in the present invention means a group of substances having two or more hydroxyl groups on the same benzene ring, and these substances include resorcinol, catechol, hydroquinone, pyrogallol, phloroglucinol and derivatives thereof. And compounds having the same structure as the above-mentioned compound in the molecule.
These compounds can be artificially synthesized, but can also be obtained from natural products such as plants.

A wide variety of polyphenol compounds are present in plants, and most of them are flavonoid compounds, ie, flavones, flavonols, flavanones, flavanonols, isoflavones, anthocyanidins, leucocyanidins and flavanols, and the like. Exist as polymers, polyhydroxy derivatives, methylated products, glycosides, etc., and most of these compounds are THE HAND
BOOK OF NATURAL FLAVONID
S (Volume1, 2) Copyright 19
99 by JOHN WILEY & SONS,
It is listed on LTD. In the present invention, those natural polyphenol compounds contained in plants are preferred, and among them, the compounds represented by the following general formula (I) are most preferred.

[0025]

Embedded image

In the formula (I), R1, R2 and R3 each represent a hydrogen atom or a hydroxyl group, and R4 represents a hydrogen atom or a galloyl group represented by the following general formula (II). )

[0027]

Embedded image

The compound represented by the above general formula (I) has asymmetric carbons at the 2- and 3-positions of the benzopyran ring. In the present invention, the kind of the isomer derived from these asymmetric carbons is not limited. Absent.

As specific examples of the compound represented by the above general formula (I), (-)-epicatechin ((-)
-Epicatechin: R1, R in formula (I)
2 represents a hydroxyl group, R3 and R4 each represent a hydrogen atom, and the 2- and 3-configurations represent 2R and 3R. ), (-)
-Catechin ((-)-catechin: in the formula (I), R1 and R2 each represent a hydroxyl group, R3 and R4 each represent a hydrogen atom, and the 2- and 3-position configurations represent 2S and 3R), (+ ) -Catechin ((+)-catechi
n: In the formula (I), R1 and R2 each represent a hydroxyl group;
3, R4 represents a hydrogen atom, and the configuration at the 2-position and 3-position represents 2R, 3S. ), (+)-Epicatechin ((+)-epicatechin: In the formula (I), R1 and R2 each represent a hydroxyl group, R3 and R4 each represent a hydrogen atom, and the configuration at the 2- and 3-positions is 2S and 3S. ), (-)-Epicatechin gallate ((-)-ep
icatechingallate: In the formula (I), R1 and R2 each represent a hydroxyl group, R3 represents a hydrogen atom, and R
4 is a galloyl group, and the configuration at the 2-position and 3-position is 2
Represents R and 3R. ), (−)-Catechin gallate ((−)-catechin gallate: In the formula (I), R 1 and R 2 each represent a hydroxyl group, R 3 represents a hydrogen atom, R 4 represents a galloyl group, and a stereo at the 2- and 3-positions) The configuration represents 2S, 3R.), (+)-Catechin gallate ((+)-catechin gallat)
e: In the formula (I), R1 and R2 each represent a hydroxyl group;
Represents a hydrogen atom, R4 represents a galloyl group, and the 2- and 3-configurations represent 2R and 3S. ), (+)-Epicatechin gallate ((+)-epicatechin)
gallate: In the formula (I), R1 and R2 each represent a hydroxyl group, R3 represents a hydrogen atom, R4 represents a galloyl group, and the 2- and 3-position configurations represent 2S and 3S. ), (-)-Epigallocatechin ((-)-epig
allocatechin: In formula (I), R1, R
2, R3 represents a hydroxyl group, R4 represents a hydrogen atom, and the configuration at the 2- and 3-positions represents 2R, 3R. ), (-)
-Gallocatechin ((-)-gallocatechi)
n: In the formula (I), R1, R2, and R3 each represent a hydroxyl group, R4 represents a hydrogen atom, and the 2- and 3-position configurations represent 2S and 3R. ), (+)-Gallocatechin ((+)-gallocatechin: In the formula (I), R1, R2, and R3 represent a hydroxyl group, R4 represents a hydrogen atom, and the 2- and 3-position configurations represent 2R and 3S. ), (+)-Epigallocatechin ((+)-epig
allocatechin: In formula (I), R1, R
2, R3 represents a hydroxyl group, R4 represents a hydrogen atom, and the configuration at the 2-position and 3-position represents 2S, 3S. ), (-)
-Epigallocatechin gallate ((-)-epigall
Ocatechin gallate: In formula (I), R1, R2, and R3 each represent a hydroxyl group, R4 represents a galloyl group, and the 2- and 3-position configurations represent 2R and 3R. ), (-)-Gallocatechin gallate ((-)-ga
Ilocatechin gallate: In the formula (I), R1, R2, and R3 each represent a hydroxyl group, R4 represents a galloyl group, and the 2- and 3-position configurations represent 2S and 3R. ), (+)-Gallocatechin gallate ((+)-g
allocatechin gallate: Formula (I)
In R1, R2, R3 represent a hydroxyl group, R4 represents a galloyl group, and the configuration at the 2-position and 3-position is 2R, 3S
Represents ), (+)-Epigallocatechin gallate ((+)-epigallocatechin gal)
late: In the formula (I), R1, R2, and R3 each represent a hydroxyl group, R4 represents a galloyl group, and the 2- and 3-configurations represent 2S and 3S. ), (−)-Epiafzelechin ((−)-epiafzelechin: Formula (I))
In R, R1, R3 and R4 each represent a hydrogen atom, R2 represents a hydroxyl group, and the 2- and 3-configurations represent 2R and 3R. ), (−)-Afzelequin ((−)-afzel)
echin: In the formula (I), R1, R3, and R4 each represent a hydrogen atom, R2 represents a hydroxyl group, and the 2- and 3-configurations represent 2S and 3R. ), (+)-Afzelechin ((+)-afzelechin: R in formula (I)
1, R3 and R4 each represent a hydrogen atom, R2 represents a hydroxyl group, and the 2- and 3-configurations represent 2R and 3S. ), (+)-Epiafzelekin ((+)-epia
fzelechin: R1, R3, R in the formula (I)
4 represents a hydrogen atom, R2 represents a hydroxyl group, and the configuration at the 2-position and the 3-position represent 2S and 3S. ), (-)-Epiafzelekingaleate ((-)-epiafzelec)
hingallate: In the formula (I), R1 and R3 represent a hydrogen atom, R2 represents a hydroxyl group, R4 represents a galloyl group, and the 2- and 3-position configurations represent 2R and 3R. ), (-)-Afzelekingallate ((-)-af
zelechingallate: R in formula (I)
1, R3 represents a hydrogen atom, R2 represents a hydroxyl group, R4 represents a galloyl group, and the configuration at the 2-position and 3-position is 2S, 3R
Represents ), (+)-Afzele quingallate ((+)-
afzelechingallate: In the formula (I), R1 and R3 represent a hydrogen atom, R2 represents a hydroxyl group, R4 represents a galloyl group, and the configuration at the 2-position and the 3-position is 2R;
Represents 3S. ), (+)-Epiafzelechingallate ((+)-epiafzelechingingallat)
e: In the formula (I), R1 and R3 represent a hydrogen atom, R2 represents a hydroxyl group, R4 represents a galloyl group, and the 2- and 3-configurations represent 2S and 3S. )and so on. Many of these compounds are derived from tea plants (Camellia sinen)
sis) leaves and stems, and green tea processed for drinking,
It is included in black tea, oolong tea, and pu-erh tea.

When a plant-derived polyphenol compound is used in the present invention, the type and site of the plant used as a raw material are not particularly limited. For example, tea trees, persimmons, chestnuts, cacao, quebrathio, mimosa, apples, citrus, grapes, blueberries And leaves, stems, xylem, bark, and rosemary
Roots, nuts and seeds, or processed products thereof can be appropriately selected and used as a raw material for the polyphenol compound.
These raw materials can be used in the present invention as they are by pulverizing them to an appropriate size.However, usually, water, hot water, a water-containing organic solvent, an organic solvent and the like are used to extract a polyphenol compound from these raw materials. Do. The final form of the extract used in the present invention may be liquid or solid (including powder). In the present invention, not only these extracts but also polyphenol compounds purified from these extracts to a desired purity can be used.

As a method for obtaining a polyphenol compound from tea, Japanese Patent Publication No. 44234/1990 and 1247/1990
4, JP-A-2-22755, JP-A-4-205
Nos. 89, 5-260907, 8-109
Specific examples are described in, for example, Japanese Patent Publication No. 178, and the above-mentioned method can also be carried out when a polyphenol compound is obtained from plants other than tea.

The foam of the present invention has a thickness of 0.5 to 10 m.
m, average bubble diameter is 0.3-2mm, apparent density is 15-
It is preferably formed as a 75 kg / m ³ sheet-like foam. The foam having such a configuration is, for example, a component of a tatami mat inserted between a tatami mat and a core material of a tatami mat, a closet, a closet, an underlaying material of a cupboard or a clog box, or a garbage bin formed by bag-making processing. When used as a bag, it can effectively trap formaldehyde and ammonia in the air. In particular, when an olefin-based resin, particularly a low-density polyethylene-based resin, is used as the base resin, an inexpensive trapping material such as formaldehyde can be obtained which is excellent in physical properties such as mechanical strength, flexibility and toughness.

If the thickness is less than 0.5 mm, it is too thin
The mechanical strength may be insufficient, and the thickness exceeds 10 mm
Is too thick and is not suitable for some applications such as tatami components
It will be. If the average bubble diameter is less than 0.3 mm,
The surface of the sheet may be uneven, resulting in poor smoothness.
Yes, when the average bubble diameter exceeds 2mm, appearance and touch
Gets worse. Apparent density is 15kg / m³Less than
Means that the expansion ratio is too large, the cell membrane becomes thin, and the mechanical strength
And the apparent density may be 75 kg / m ³Over
The tatami components and the closet
It is inconvenient to use as an underlaying material.

The foam of the present invention has a thickness of 10 to 70.
mm, average cell diameter 0.2 to 5 mm, apparent density 22
It is preferably formed as a plate having a cross section perpendicular to the longitudinal direction of 25 to 100 kg / m ³ and an area of 25 cm ² or more. The foam having such a configuration is suitable, for example, as a building material having both heat insulation and formaldehyde trapping ability. When used in such applications, the use of polyethylene resin as the base resin, mechanical properties,
It is preferable in terms of the balance between flexibility and price. For applications requiring compressive strength and rigidity, polystyrene resins are preferable.

When the thickness is less than 10 mm, the heat insulating property may be insufficient, and when the thickness exceeds 70 mm, the foam may be too thick and may not contribute to capture of formaldehyde. There is a possibility that formaldehyde scavenging ability or the like corresponding to the added amount may not be obtained. If the average bubble diameter is less than 0.2 mm,
Since the cell membrane becomes thin, the compressive strength may decrease. If the average cell diameter exceeds 5 mm, the appearance and heat insulation may deteriorate. When the apparent density is less than 22 kg / m ^{3, the} mechanical strength may be reduced because the cell membrane becomes thin,
When the apparent density exceeds 100 kg / m ³ , there is a possibility that the heat insulating property is deteriorated.

The foam of the present invention has an apparent density of 20.
It is preferably formed as a rod-shaped long foam or a tubular long foam having cracks continuous in the longitudinal direction, having a length of 100 kg / m ³ and a cross section perpendicular to the longitudinal direction of 5 cm ² or more. Such a long foam can be used as a joint material or the like, and a long tubular foam can be used, for example, to expand cracks in the long tubular foam on pillars, handrails, doors, windows, etc. of a new house. It can be suitably used as a protective material for a building or the like that protects a building when a household property is carried in. When used in the above applications, it is preferable to use a polyethylene resin as the base resin in terms of mechanical properties, flexibility, and buffering properties.

In the present specification, the apparent density of the foam is a value measured based on JIS K7222-1985. The thickness of the foam is JIS K722.
It is a value measured based on the method for measuring the thickness of a test piece in 2-1985.

The method for measuring the average cell diameter of the foam in the present specification is as follows. The average cell diameter (a) in the thickness direction and the average cell diameter (b) in the width direction are the vertical cross section of the foam board (vertical cross section orthogonal to the extrusion direction of the foam board).
The average cell diameter (c) in the extrusion direction is determined by using a microscope or the like with a cross section perpendicular to the extrusion direction of the foam board (the foam board is bisected in the width direction and perpendicular to the width direction of the foam board). To project on a screen or monitor, draw a straight line in the direction to be measured on the projected image, count the number of bubbles intersecting the straight line, and calculate the length of the straight line (however, this length is The average bubble diameter in each direction is obtained by dividing the length of a true straight line in consideration of the magnification of the projected image, not the length of the straight line on the projected image, by the number of counted bubbles. .

However, the average bubble diameter (a) in the thickness direction was measured by drawing straight lines over the entire thickness in the thickness direction at a total of three places at the center and both ends of the cross section perpendicular to the width direction, and measuring the length of each straight line and the straight line From the number of bubbles intersecting with the average diameter of the bubbles existing on each straight line (length of the straight line / number of bubbles intersecting the straight line),
The arithmetic mean value of the obtained average diameters at three locations is defined as the average bubble diameter (a) in the thickness direction.

The average cell diameter (b) in the width direction is determined by dividing a straight line having a length of 3000 μm into two parts in the thickness direction by dividing a total of three foam plates at the center and both ends of the cross section perpendicular to the width. From the straight line having a length of 3000 μm and (the number of bubbles intersecting the straight line-1), the average diameter of bubbles existing on each straight line (3000 μm / (the number of bubbles intersecting the straight line−
1)) is obtained, and the arithmetic mean value of the obtained average diameters at three locations is defined as an average bubble diameter (b) in the width direction.

The average cell diameter (c) in the extrusion direction is determined by drawing a straight line having a length of 3000 μm at a position where the foam plate at a total of three places at the center and both ends of the vertical cross section is bisected in the thickness direction. Direction, the average diameter of the bubbles existing on each straight line (3000 μm / (the number of bubbles intersecting the straight line-1)) from the 3000 μm long straight line and (the number of bubbles intersecting the straight line-1) The arithmetic mean value of the calculated average diameters at the three locations is defined as the average bubble diameter (c) in the extrusion direction.

The arithmetic average value of the average cell diameters (a), (b) and (c) obtained as described above is defined as the average cell diameter of the foam.

The foam of the present invention preferably contains a deodorant. By adding the deodorant to the foam, the odor peculiar to the foam to which the polyphenol compound is added can be reduced. In addition, even during the production of the foam, the generation of odor caused by the polyphenol compound to be added can be reduced.

Examples of the deodorizing agent include charcoal, activated carbon, zeolite, synthetic zeolite, tourmaline, and the like, which do not significantly reduce the deodorizing performance under high-temperature and high-pressure production conditions for foams. As the deodorizing agent, a deodorizing agent containing a silicon compound having a deodorizing property such as hydrous silicic acid is preferable because of its excellent formaldehyde trapping ability and particularly high trapping rate. It is considered that the reason for this is that, since the deodorant contains a silicon compound, the foam to which the deodorant has been added has increased alkalinity, thereby increasing the rate of the binding reaction between formaldehyde and the polyphenol compound.

The amount of the deodorant added to the foam is 0.01 to 10% by weight, preferably 0.1 to 10% by weight, based on the weight of the foam.
5% by weight, more preferably 0.1 to 2% by weight. When the addition amount is less than 0.01% by weight,
Sufficient deodorizing effect cannot be obtained. On the other hand, when the addition amount exceeds 10% by weight, there is a possibility that a problem may occur due to a decrease in the average cell diameter of the foam.

Hereinafter, a preferred production example of the foam of the present invention will be described. The foam of the present invention made of a polystyrene resin is a melt flow rate (hereinafter, referred to as MFR).
Is obtained by adding an expandable molten resin composition obtained by adding 0.01 to 20% by weight of a polyphenol compound and a physical blowing agent to a polystyrene resin of 0.5 to 35 g / 10 minutes from a high pressure range to a low pressure range using an extruder. It can be obtained by extrusion foaming. After adjusting the foamable molten resin composition having such a configuration to an appropriate temperature and extruding from a high pressure range to a low pressure range using an extruder, a polystyrene resin foam excellent in formaldehyde trapping ability and the like can be easily obtained. Can be.

The polystyrene resin has an MFR of 0.5 g /
If the time is less than 10 minutes, the extrusion pressure is increased, and as a result, the temperature of the foamable molten resin composition becomes too high, so that the polyphenol compound may be decomposed. On the other hand, MFR is 3
If the amount exceeds 5 g / 10 minutes, the polyphenol compound tends to reduce the foaming property of the polystyrene resin, so that a high-quality foam may not be obtained.
However, the MFR of the polystyrene resin is JIS K72
It shall be measured under the conditions of a temperature of 200 ° C. and a load of 49.03 N.

The physical foaming agent used to obtain the foam of the present invention comprising a polystyrene resin includes propane, n-butane, i-butane, a mixture of n-butane and i-butane, pentane, hexane and the like. Aliphatic hydrocarbons,
Cycloaliphatic hydrocarbons such as cyclobutane and cyclopentane, trichlorofluoromethane, dichlorodifluoromethane, 1,1-difluoroethane, 1,1-difluoro-
Examples include halogenated hydrocarbons such as 1-chloroethane, 1,1,1,2-tetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride; inorganic gases such as carbon dioxide and nitrogen; water; and mixtures thereof.

In the present invention, a decomposable blowing agent such as azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, and sodium bicarbonate can be used in combination.

However, it is preferable to use a material which does not contain chlorofluorocarbon which may have a bad influence on the environment such as destruction of the ozone layer. In addition, an organic physical foaming agent is used in 50
It is preferable to use a physical foaming agent containing not less than% by weight.
Since the apparent density of the foam varies depending on the type of the base resin, the type of the foaming agent, the amount of the foaming agent, and the amount of the foaming agent, the desired apparent density is obtained according to the type of the foaming agent and the type of the base resin. It is necessary to select the amount of the foaming agent to be added.

In the formation of a foam, a cell regulator is used together with a physical foaming agent. As the bubble regulator,
Examples include inorganic powders such as talc and silica, acidic salts of polyvalent carboxylic acids, and reaction mixtures of polyvalent carboxylic acids with sodium carbonate or sodium bicarbonate.

When the amount of the polyphenol compound added is 0.01
If the amount is less than 10% by weight, the desired formaldehyde trapping ability may not be obtained. On the other hand, if the amount exceeds 20% by weight, the foaming ability of the polystyrene-based resin may be reduced, and a high-quality foam may not be obtained.

The foam of the present invention comprising a polypropylene resin is prepared by adding a polyphenol compound of 0.01 to 20% by weight to a polypropylene resin having an MFR of 0.3 to 15 g / 10 min and a melt tension of 4 to 30 gf. The foamable molten resin composition to which the agent has been added can be obtained by extrusion foaming from a high pressure range to a low pressure range using an extruder. After adjusting the foamable molten resin composition having such a configuration to an appropriate temperature and extruding from a high pressure range to a low pressure range using an extruder, it is possible to easily obtain a polypropylene resin foam excellent in formaldehyde trapping ability and the like. Can be.

If the melt flow rate of the polypropylene resin is less than 0.3 g / 10 minutes, the extrusion pressure becomes too high and the temperature of the foamable molten resin composition becomes too high, so that the polyphenol compound may be decomposed. is there. On the other hand, when the MFR exceeds 15 g / 10 minutes, the polyphenol compound tends to decrease the foaming property of the polypropylene resin, and thus it may not be possible to obtain a high-quality foam. However, MFR of polypropylene resin
Means a temperature of 230 ° C. and a load of 21.degree.
It shall be measured under the condition of 18N.

The melt tension of the polypropylene resin is 4 gf
If it is less than 3, the molten resin may not withstand the foaming force during foaming and the cell membrane may be broken. On the other hand, the melt tension is 30 gf
Exceeding the limit causes the tension of the molten resin at the time of foaming to be too large, thereby hindering the growth of air bubbles. Therefore, a low-density foam may not be obtained.

The melt tension (melt tension: MT) of the polypropylene resin was measured using a melt tension tester type II manufactured by Toyo Seiki Seisaku-Sho, Ltd., using a nozzle having a nozzle inner diameter of 2.095 mm and a length of 8 mm, and measuring the resin temperature. The measurement is performed under the conditions of extrusion at 230 ° C., a piston speed of 10 mm / min, and a winding condition of a resin string at a winding speed of 100 rpm with a roll having a diameter of 5 cm. However, when the resin string is cut before the winding speed reaches 100 rpm, the MT at the time when the resin string is cut is defined as the MT of the polypropylene resin.

The constitutions of the physical foaming agent and the polyphenol compound are the same as those of the foam made of the polystyrene resin described above. The use of a decomposable foaming agent and the use of a cell regulator are also the same as those in the case of a foam made of a polystyrene resin.

The foam of the present invention comprising a polyethylene resin has an MFR of 0.1 to 30 g / 10 min and a density of 940.
A foamable molten resin composition in which 0.01 to 20% by weight of a polyphenol compound and a physical foaming agent are added to a polyethylene resin of not more than kg / m ³ by extrusion foaming from a high pressure range to a low pressure range using an extruder. Can be obtained. After adjusting the foamable molten resin composition having such a configuration to an appropriate temperature and extruding from a high pressure range to a low pressure range using an extruder, it is possible to easily obtain a polyethylene resin foam excellent in formaldehyde trapping ability and the like. Can be.

The polyethylene resin has an MFR of 0.1 g /
If the time is less than 10 minutes, the extrusion pressure is increased, and as a result, the temperature of the foamable molten resin composition becomes too high, so that the polyphenol compound may be decomposed. On the other hand, MFR is 3
If the amount exceeds 0 g / 10 minutes, the polyphenol compound tends to lower the foaming property of the polyethylene resin, so that a high-quality foam may not be obtained.
However, the MFR of the polyethylene resin is 190 ° C.
It shall be measured under the condition of a load of 21.18N.

The density of the polyethylene resin is 940 kg /
If exceeding m ^3, there is a concern that it is difficult to obtain a foam of good quality for crystallinity is too high.

The constitutions of the physical foaming agent and the polyphenol compound are the same as those of the foam made of the polystyrene resin described above. The use of a decomposable foaming agent and the use of a cell regulator are also the same as those in the case of a foam made of a polystyrene resin.

In any of the above-mentioned extrusion foaming steps of a foam made of a polystyrene resin, a polypropylene resin, and a polyethylene resin, the temperature of the molten resin in the extrusion foaming step was measured with a thermocouple or the like.
It is preferable to adjust the extrusion conditions so as to be 0 ° C. or lower. If the maximum temperature exceeds 220 ° C., the decomposition of the polyphenol compound may become severe, and the desired capturing ability of formaldehyde or the like may not be obtained.

The maximum temperature reached in the extrusion foaming step is measured by inserting a thermocouple into the barrel at several points of the extruder and measuring the temperature of the resin in the barrel.

In order to produce the foam so that the maximum temperature is not more than 220 ° C., it is necessary to turn on / off a band heater mounted on the barrel of the extruder or to circulate the refrigerant through the barrel or screw of the extruder. It can be achieved by adjusting the temperature by a method for causing the above.

When producing the foam of the present invention,
In the aforementioned extrusion foaming method, the foamable molten resin composition is extruded under atmospheric pressure through an annular die provided at the tip of the extruder to foam into a tubular shape, and the tubular foam is cut open along the extrusion direction and foamed. Examples of the method include a method of forming a sheet, a method of forming a plate-like foam through a flat die, and a method of forming various kinds of foams having different cross-sectional shapes through a deformed die.

The thickness is 10 to 70 mm, the average bubble diameter is 0.2 to 5 mm, and the apparent density is 22 to 100 kg / m2.
³ , a foam having an area of 25 cm ² or more perpendicular to the longitudinal direction or an apparent density of 20 to 100 kg /
m ³ , in the case of producing a rod-shaped long foam or a tubular long foam having a crack continuous in the longitudinal direction, having an area of a cross section perpendicular to the longitudinal direction of 5 cm ² or more, between the extruder and the die An accumulator may be provided. By providing an accumulator, the discharge speed can be dramatically increased, so that it is easy to obtain the foam of the present invention having a high expansion ratio and a high thickness.

[0067]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

In the following Examples and Comparative Examples, two types of green tea extracts shown in Table 1 were used as polyphenol compound-containing substances.

[0069]

[Table 1]

Example 1 A polystyrene resin (86 parts by weight) having an MFR of 19 g / 10 min, talc (10 parts by weight) as a cell regulator,
The raw material mixed with green tea extract A (4 parts by weight) is supplied to an extruder, heated and kneaded to form a molten resin, and then methyl chloride (3 parts per 100 parts by weight of the mixed raw material) is used as a physical blowing agent. (0.5 parts by weight) into a molten resin in an extruder to form a foamable molten resin mixture, and then kneaded to adjust the temperature to a foamable temperature. Next, the foamable molten resin mixture was extruded from a flat die having an outlet gap of 2 mm and a width of 115 mm,
A plate-like foam was produced.

Example 2 A plate-like foam was formed in the same manner as in Example 1 except that a polystyrene resin having an MFR of 0.6 g / 10 min was used.

Example 3 A polystyrene resin having an MFR of 19 g / 10 min (96.6)
Parts by weight) and talc (2 parts by weight) as a foam regulator
And a green tea extract A (1.4 parts by weight) are mixed and supplied to an extruder, which is heated and kneaded to obtain a molten resin.
A mixed blowing agent in which isobutane and normal butane are blended at a weight ratio of 3 to 7 as a physical blowing agent (the mixed raw material 1)
(6 parts by weight with respect to 00 parts by weight) into the molten resin in the extruder and further kneaded to form a foamable molten resin mixture.
The temperature was adjusted to allow foaming. Next, the foamable molten resin mixture was extruded from an annular die to produce a sheet-like foam.

Example 4 A polystyrene resin having an MFR of 19 g / 10 min (82.1
Parts by weight), a raw material obtained by mixing talc (2.5 parts by weight) as a cell regulator and green tea extract B (15.4 parts by weight). A sheet-like foam was produced in the same manner as in Example 3 except that the amount was 0.5 part by weight.

Comparative Example 1 A raw material obtained by mixing a polystyrene resin (90 parts by weight) with an MFR of 19 g / 10 min and talc (10 parts by weight) as a foam regulator was used, except that green tea extract A was not added. In the same manner as in Example 1, a plate-like foam was produced.

Comparative Example 2 A raw material obtained by mixing a polystyrene resin (98 parts by weight) having an MFR of 19 g / 10 min and talc (2 parts by weight) as a foam regulator was used, except that green tea extract A was not added. A sheet-like foam was produced in the same manner as in Example 3.

Comparative Example 3 A polystyrene resin having an MFR of 19 g / 10 min (36.5)
Parts by weight) and talc (2 parts by weight) as a cell regulator
A sheet-like foam was produced in the same manner as in Example 3, except that a raw material mixed with green tea extract B (61.5 parts by weight) was used. However, the resulting sheet had non-uniform air bubbles and a poor appearance.

Table 2 shows the maximum temperature reached during extrusion, the open cell ratio, apparent density, thickness, width, and average cell diameter of the obtained foam in Examples 1 to 4 and Comparative Examples 1 to 3.

[0078]

[Table 2]

Example 5 A polypropylene resin (94.6 parts by weight) having an MFR of 3 g / 10 min and a melt tension of 20 gf, sodium citrate (0.1 parts by weight) as a cell regulator, and talc (0.1 parts by weight) were used.
3 parts by weight) and a raw material obtained by mixing green tea extract A (5.0 parts by weight) to an extruder, heating and kneading to obtain a molten resin, and then isobutane (the above mixed raw material) as a physical foaming agent. (8 parts by weight with respect to 100 parts by weight) was injected into the molten resin in the extruder and kneaded to form a foamable molten resin mixture, which was then adjusted to a foamable temperature. Next, the foamable molten resin mixture was extruded from an annular die to produce a sheet-like foam. A through-hole was formed in the obtained sheet-like foam using the apparatus shown in FIG.

Comparative Example 4 A polypropylene resin (99.6 parts by weight) having an MFR of 3 g / 10 min and a melt tension of 20 gf, sodium citrate (0.1 parts by weight) as a cell regulator, and talc (0.1 parts by weight) were used.
3 parts by weight) and green tea extract A
A sheet-like foam was produced in the same manner as in Example 5 except that (5.0 parts by weight) was not added, and a through-hole was formed in the sheet-like foam obtained in the same manner as in Example 5. .

Table 3 shows the maximum temperature reached during extrusion, the open cell ratio, apparent density, thickness, width and average cell diameter of the obtained foam in Example 5 and Comparative Example 4.

[0082]

[Table 3]

Example 6 A polyethylene resin (78.8 parts by weight) having an MFR of 4.5 g / 10 min and a density of 916 kg / m ³ , 5 parts by weight of sodium citrate and 100 parts by weight of a polyethylene-based resin and talc 10 parts by weight of a foam control agent masterbatch C (4.8 parts by weight) and polyethylene resin 10
0 parts by weight of 1 grey monostearate
2 parts by weight of a shrinkage preventing masterbatch D (11.
4 parts by weight) and a raw material obtained by mixing green tea extract A (5.0 parts by weight) to an extruder, heating and kneading to obtain a molten resin, and then isobutane and normal butane are used as physical blowing agents. A mixed foaming agent (6.0 parts by weight with respect to 100 parts by weight of the mixed raw material) blended in a weight ratio of 3 to 7 is press-fitted into the molten resin in the extruder, and further kneaded to form a mixture with the foamable molten resin mixture. After that, the temperature was adjusted to a temperature at which foaming was possible. Next, the foamable molten resin mixture was extruded from an annular die to produce a sheet-like foam.

Example 7 A through-hole was formed in the sheet-like foam obtained in Example 6 using the apparatus shown in FIG.

Example 8 A polyethylene resin (80.9 parts by weight) having an MFR of 2.4 g / 10 min and a density of 922 kg / m ³ , the master batch C (4.9 parts by weight), and the shrinkage preventing master Using a raw material obtained by mixing batch D (11.7 parts by weight) and green tea extract A (2.5 parts by weight), 6.0 parts by weight of the mixed foaming agent was added to 100 parts by weight of the mixed raw material. A sheet-like foam was produced in the same manner as in Example 6, except that the molten resin was press-fitted into the extruder. A through-hole was formed in the obtained sheet-like foam using the apparatus shown in FIG.

Example 9 A polyethylene resin (79.8 parts by weight) having an MFR of 2.4 g / 10 min and a density of 922 kg / m ³ , the foam control master batch C (5.7 parts by weight), Shrinkage prevention master batch D (9.5 parts by weight) and green tea extract A
(5.0 parts by weight) was supplied to an extruder, and heated and kneaded to obtain a molten resin, and then isobutane (5 parts per 100 parts by weight of the mixed raw material) was used as a physical foaming agent.
(0 parts by weight) was injected into the molten resin in the extruder, and further kneaded to form a foamable molten resin mixture, which was then adjusted to a foamable temperature. Next, the foamable molten resin mixture is supplied to the outlet gap 3
The sheet was extruded from a flat die having a width of 80 mm and a width of 80 mm to produce a plate-like foam. A through-hole was formed in the obtained plate-shaped foam using the apparatus shown in FIG.

Example 10 A polyethylene resin (72.0 parts by weight) having an MFR of 4.5 g / 10 min and a density of 916 kg / m ³ , the foam control master batch C (2.5 parts by weight), Shrinkage prevention master batch D (10.1 parts by weight) and green tea extract B
(15.4 parts by weight), and a sheet-like foam was produced in the same manner as in Example 6 except that 6.0 parts by weight of the mixed foaming agent was press-fitted. A through-hole was formed in the foam of the obtained sheet using the apparatus shown in FIG.

Example 11 A polyethylene resin (78.8 parts by weight) having an MFR of 0.2 g / 10 min and a density of 915 kg / m ³ , the foam control master batch C (4.8 parts by weight), Shrinkage prevention master batch D (11.4 parts by weight) and green tea extract A
(5.0 parts by weight), and a foamed sheet was produced in the same manner as in Example 6, except that the mixed foaming agent was press-fitted in an amount of 12.0 parts by weight. A through-hole was formed in the foam of the obtained sheet using the apparatus shown in FIG.

Comparative Example 5 A polyethylene resin (82 parts by weight) having an MFR of 4.5 g / 10 min and a density of 916 kg / m ³ , the foam control master batch C (6 parts by weight), and the shrinkage preventing master batch D (12 parts by weight), and a raw material to which the green tea extract A was not added was used.
A sheet-like foam was produced in the same manner as in Example 6, except that 0 parts by weight was pressed.

Comparative Example 6 A through-hole was formed in the plate-like foam obtained in Comparative Example 5 using the apparatus shown in FIG.

Comparative Example 7 A sheet-like foam was produced in the same manner as in Example 8, except that no through-hole was formed.

Comparative Example 8 A polyethylene resin (84 parts by weight) having an MFR of 2.4 g / 10 min and a density of 922 kg / m ³ , the cell regulator master batch C (6 parts by weight), and the shrinkage preventing master batch D (10 parts by weight), and a plate-like foam was produced in the same manner as in Example 9 except that a raw material to which the green tea extract A was not added was used. A through-hole was formed in the obtained plate-shaped foam using the apparatus shown in FIG.

Comparative Example 9 A polyethylene resin (46.3 parts by weight) having an MFR of 4.5 g / 10 min and a density of 916 kg / m ³ , the cell regulator master batch C (1.0 part by weight), Shrinkage prevention master batch D (6.5 parts by weight) and green tea extract B
(46.2 parts by weight), and a foamed sheet was produced in the same manner as in Example 6, except that 6.0 parts by weight of the mixed foaming agent was press-fitted. However, the resulting sheet had non-uniform air bubbles and a poor appearance.

Comparative Example 10 A polyethylene resin (78.8 parts by weight) having an MFR of 65 g / 10 min and a density of 915 kg / m ³ , the foam control master batch C (4.8 parts by weight), and the shrinkage prevention Master batch D (11.4 parts by weight) and green tea extract A
(5 parts by weight), and a sheet-like foam was produced in the same manner as in Example 6, except that 6.0 parts by weight of the mixed foaming agent was press-fitted. However, the resulting sheet had non-uniform air bubbles and a poor appearance.

Table 4 shows the maximum temperature reached during extrusion, the open cell ratio, apparent density, thickness, width, and average cell diameter of the obtained foam in Examples 6 to 11 and Comparative Examples 5 to 10.

[0096]

[Table 4]

[0097] Example 12 to 17 MFR is 4.5 g / 10 min, density of 916 kg / ^{m 3} of polyethylene resin and, cell regulators masterbatch talc 20 parts by weight per 100 parts by weight of polyethylene resin is blended A masterbatch containing 12 parts by weight of greycellide monostearate with respect to 100 parts by weight of a polyethylene resin; green tea extract B; Hydrous silicate compound (trade name: manufactured by Chemical Industry Co., Ltd.)
Dime shoe 6000P) 30 parts by weight of a deodorant masterbatch mixed with the mixture shown in Table 8 were fed to an extruder, heated and kneaded to obtain a molten resin.
A mixed blowing agent in which isobutane and normal butane are blended at a weight ratio of 3 to 7 as a physical blowing agent (the mixed raw material 1)
(7.0 parts by weight with respect to 00 parts by weight) was injected into the molten resin in the extruder, and further kneaded to form a foamable molten resin mixture, which was then adjusted to a foamable temperature. Next, the foamable molten resin mixture was extruded from an annular die to produce a sheet-like foam. A through-hole was formed in the obtained sheet-like foam using the apparatus shown in FIG.

Example 18 A sheet-like foam was produced in the same manner as in Example 12 except that no through-hole was formed using the apparatus shown in FIG.

Table 9 shows the amount of the polyphenol compound added and the maximum temperature reached during extrusion in Examples 12 to 18, and the shape, open cell ratio, apparent density, thickness,
Table 10 shows the width and the average bubble diameter.

The evaluation of the odors in Table 10 (the odors were odors like roasted tea, sweet odors like heating sugar, and acid odors like sticking to the nose) were based on the following criteria. Was evaluated. ：: Almost no odor was felt during production, and no odor was felt from the obtained foam. ：: Some odor is felt during production, but no odor is felt from the obtained foam. Δ: There is considerable odor at the time of production, and some odor is felt from the obtained foam. Formaldehyde concentration tests and ammonia concentration tests were performed on the foamed boards obtained in Examples 1 to 4 and Comparative Examples 1 to 3. Table 5 shows the results.

The foamed boards obtained in Example 5 and Comparative Example 4 were subjected to a formaldehyde concentration test and an ammonia concentration test. Table 6 shows the results.

The foamed boards obtained in Examples 6 to 18 and Comparative Examples 5 to 10 were subjected to a formaldehyde concentration test and an ammonia concentration test. The results are shown in Tables 7 and 11.

[0103]

[Table 5]

[0104]

[Table 6]

[0105]

[Table 7]

[0106]

[Table 8]

[0107]

[Table 9]

[0108]

[Table 10]

[0109]

[Table 11]

The formaldehyde test was performed as follows. As shown in FIG. 2, a crystallizing dish 12 containing distilled water was placed at the bottom of a desiccator 11, and an intermediate plate 13 was placed thereon. On the middle plate 13, a foam 14 to be tested,
Place the filter paper 15 on which the formaldehyde solution has been dropped, and place the cover 1
6 and left in a constant temperature / humidity room at 20 ° C. and RH 65%. After a predetermined time, the concentration of formaldehyde dissolved in distilled water in the crystallization dish 12 was measured by the acetylacetone method, and the amount of formaldehyde absorbed was determined. In addition, foam 1
When 4 is a sheet, 10 sheets of 100 mm long × 150 mm wide are used, and when 4 is a sheet, 100 mm long × 150 mm wide
2 mm were used.

Ammonia Concentration Test As shown in FIG. 3, a foam 22 was placed in a wide-mouthed reagent bottle 21, and a filter paper 23 was placed thereon. After sealing the mouth of the wide-mouthed reagent bottle 21 with aluminum foil 24, a needle (not shown) of a microsyringe was pierced into the aluminum foil 24, and 10 μl of a 5% aqueous ammonia solution was dropped on the filter paper 23. Immediately cover the pinhole 25 of the aluminum foil 24 with the needle with the vinyl tape 26,
5 ° C.). After a lapse of a predetermined time, the ammonia gas concentration in the head space 27 was measured using a gas detection tube. In addition, three sheets of foam 22 having a length of 100 mm and a width of 150 mm were used.

[0112]

The thermoplastic resin foam of the present invention is easy to recycle because the base resin is formed of a polystyrene resin or a polyolefin resin. Also, 0.
Since the polyphenol compound is added in an amount of from 0.01 to 20% by weight, it has a formaldehyde trapping ability, has an open cell ratio of 5% or more, and has an increased contact area with formaldehyde. Etc. are further improved. That is, the thermoplastic resin foam of the present invention is chemically adsorbed by a polyphenol compound,
Due to the synergistic effect of the increase in the adsorption area due to the foam having the open-cell structure, it is particularly excellent in the ability to capture problematic substances such as formaldehyde, and furthermore, it is excellent in practicality that also has the excellent buffering and heat insulating properties of the foam. .

Therefore, the foam of the present invention is a material excellent as a building material having both heat insulating properties and formaldehyde trapping ability, a packaging material having both buffering properties and formaldehyde trapping ability, a curing material and miscellaneous goods.

In the present invention, the use of a polyphenol compound having a specific structure such as (−)-epicatechin, (−)-epicatechin gallate, (−)-epigallocatechin gallate, (−)-epigallocatechin gallate, and the like is more effective. Excellent formaldehyde trapping ability can be obtained.

In the present invention, when a sheet-like foam having a thickness, an average cell diameter, and an apparent density within a specific range is provided, it becomes excellent as a member for a tatami mat, a closet or an underlaying material for a closet. In the present invention, the thickness,
When the average cell diameter, the apparent density, and the area of the cross section perpendicular to the longitudinal direction are configured as a plate-like foam within a specific range, it is suitable as a building material having both heat insulation and formaldehyde trapping ability.

In the present invention, by forming a foam to which a deodorant is added, the odor of the obtained foam due to the polyphenol compound can be reduced. In addition, the odor during the production of the foam can be reduced. Further, when the deodorizing agent contains a silicon compound having deodorizing properties, in particular, hydrous silicic acid, it is possible to obtain a thermoplastic resin foam further improved in formaldehyde trapping ability in addition to the effect of reducing the odor.

In the method for producing a thermoplastic resin foam of the present invention, a foamable molten resin composition obtained by adding a physical blowing agent and a specific range of a polyphenol compound to a polystyrene resin having a specific range of melt flow rate is used. By extruding and foaming from a high pressure region to a low pressure region using an extruder, a polystyrene resin foam having formaldehyde trapping ability and the like can be easily obtained.

In the method for producing a thermoplastic resin foam of the present invention, a foamable molten resin composition comprising a physical foaming agent and a specific range of a polyphenol compound added to a polypropylene resin having a specific range of melt flow rate and melt tension. By extruding and foaming the product from a high-pressure region to a low-pressure region using an extruder, a polypropylene resin foam having formaldehyde trapping ability and the like can be easily obtained.

In the method for producing a thermoplastic resin foam of the present invention, a foamable molten resin composition comprising a polyethylene resin having a specific range of melt flow rate and density, and a physical foaming agent and a polyphenol compound having a specific range are added. Is extruded from a high-pressure region to a low-pressure region using an extruder, whereby a polyethylene resin foam having formaldehyde trapping ability and the like can be easily obtained.

In the method for producing a thermoplastic resin foam of the present invention, the maximum temperature reached in the extrusion foaming step is 220.
By adjusting the extrusion conditions so as to be lower than or equal to ° C., it is possible to prevent the degradation of the formaldehyde trapping ability and the like due to the decomposition of the polyphenol compound.

[Brief description of the drawings]

FIG. 1 is a drawing showing an example of a through hole forming apparatus.

FIG. 2 is an explanatory diagram of a method for measuring the formaldehyde concentration.

FIG. 3 is an explanatory diagram of a method for measuring an ammonia concentration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Through-hole forming apparatus 2 Needle roll 3 Receiving roll 4 Needle for through-hole formation 5 Foam 6 Foam with through-hole formed

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/1545 C08K 5/1545 C08L 23/00 C08L 23/00 25/04 25/04 // B29K 23: 00 B29K 23:00 25:00 25:00 105: 04 105: 04 (72) Inventor Yuichiro Hashizume 10-3 Satsuki-cho, Kanuma-city, Tochigi Prefecture JSP Kanuma Research Institute, Inc. (72) Naotochi Kogure, Tochigi Prefecture 10-3 Satsuki-cho, Kanuma City Inside the JSP Kanuma Research Laboratories Co., Ltd. (72) Inventor Seiji Takahashi 10-3 Satsuki-cho, Kanuma City, Tochigi Pref. -1 Tokyo Food Tech Kuno Co., Ltd. Central Research Laboratory (72) Inventor Hiroshi Hojo 223-1 Miyahara Fujieda-shi, Shizuoka Prefecture Tokyo Food Tech Kuno Co., Ltd. In-house (72) Inventor Kazuki Kaneyama 3-2-11 Nishi-Shinjuku, Shinjuku-ku, Tokyo Mitsui Norin Co., Ltd.F-term (reference) BA53 CA22 DA02 DA03 DA13 DA23 DA32.

Claims (11)

[Claims] 1. A foam comprising a polystyrene resin or a polyolefin resin, having an open cell ratio of 5% or more and a polyphenol compound of 0.01 to 20%.
A thermoplastic resin foam, which is added by weight%. 2. The thermoplastic resin foam according to claim 1, wherein the thickness is 0.5 to 10 mm, the average cell diameter is 0.3 to 2 mm, and the apparent density is 15 to 75 kg / m ³ . 3. The thickness is 10 to 70 mm, and the average bubble diameter is
0.2-5mm, apparent density 22-100kg /
m³, The area of the cross section perpendicular to the longitudinal direction is 25 cm ²Less than
The thermoplastic resin according to claim 1, wherein:
Foam. 4. The thermoplastic resin foam according to claim 1, wherein the polyphenol compound is a compound represented by the following general formula (I). Embedded image (However, in the formula (I), R1, R2, and R3 each represent a hydrogen atom or a hydroxyl group, and R4 represents a hydrogen atom or a galoilo group represented by the following general formula (II).) 2] 5. The thermoplastic resin foam according to claim 1, further comprising a deodorant. 6. The thermoplastic resin foam according to claim 5, wherein the deodorizing agent contains a silicon compound having a deodorizing property. 7. The thermoplastic resin foam according to claim 6, wherein the deodorizing silicon compound is hydrous silicic acid. 8. Melt flow rate is 0.5 to 35 g /
Extruding and foaming a foamable molten resin composition obtained by adding a polyphenol compound in an amount of 0.01 to 20% by weight and a physical blowing agent to a polystyrene resin for 10 minutes from a high pressure range to a low pressure range using an extruder. A method for producing a thermoplastic resin foam. 9. The melt flow rate is from 0.3 to 15 g /
A foamable molten resin composition obtained by adding a polyphenol compound at 0.01 to 20% by weight and a physical foaming agent to a polypropylene resin having a melt tension of 4 to 30 gf for 10 minutes is subjected to a low pressure to a high pressure range using an extruder. A method for producing a thermoplastic resin foam, characterized by extruding foam in a region. 10. Melt flow rate is 0.1 to 30 g.
/ 10 minutes, 0.01-20% by weight of a polyphenol compound in a polyethylene resin having a density of 940 kg / m ³ or less.
A method for producing a thermoplastic resin foam, comprising extruding a foamable molten resin composition to which a physical foaming agent is added from a high pressure range to a low pressure range using an extruder. 11. The thermoplastic resin foam according to claim 8, wherein the extrusion conditions are adjusted so that the maximum temperature of the molten resin in the extrusion foaming step is 220 ° C. or lower. Production method.