JP2003313345A - Thermoplastic resin foam and method for producing thermoplastic resin foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin foam being excellent in the capacity to catch formaldehyde, ammonia, etc., reduced in the emission of a characteristic odor, and having an excellent appearance and to provide a method for stably producing the foam. <P>SOLUTION: The thermoplastic resin foam contains a composition comprising a zinc compound, a weakly alkaline inorganic substance, and hydrated silicic acid and a polyphenol compound. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin foam having a formaldehyde scavenging ability, an ammonia scavenging ability and the like, and a method for producing the foam.

[0002]

2. Description of the Related Art In recent years, indoor air pollution due to various volatile gases has become an important problem as housings have become highly airtight and highly insulating. Formaldehyde is one of such volatile gases, and it is said that formaldehyde is emitted into the room from building materials, building interior materials, furniture, etc., and irritates the eyes, nose, throat, etc., causing allergies and the like. In view of such a situation, it is necessary to take measures to absorb and remove the formaldehyde released indoors, and the regulation standard value of the indoor formaldehyde concentration has also been set.

On the other hand, it is known that polyphenol compounds derived from plants have high reactivity with formaldehyde and are harmless to the human body and have no volatility, so that they do not cause secondary pollution. A sheet or the like having a formaldehyde-capturing ability and the like by containing the polyphenol compound has been proposed.

Further, the present applicants have previously filed an application regarding a thermoplastic resin foam which is a foam excellent in trapping formaldehyde, ammonia and the like and which is produced by blending a polyphenol compound with a resin and extruding and foaming. (Japanese Patent Application No. 2001-303716).

In the above-mentioned application of the applicants, since the thermoplastic resin foam containing a polyphenol compound usually has a peculiar odor, it is described that a deodorant is added to the base material composition in order to reduce the odor. Has been done.

However, although the method of adding a deodorizing agent for reducing odor is certainly effective, when the foam is continuously produced for a long time, dust and the like in the resin melt are removed in the extruder. There was a new problem that the mesh of the screen breaker was clogged with lumps of impurities. If the mesh is clogged, manufacturing conditions such as die pressure fluctuations will become unstable, so it will be necessary to frequently replace the mesh to remove impurities, and the granular lumps that cannot be completely removed by the mesh will be foam. However, there was a new problem to be solved such as deterioration of the surface condition of the foam.

[0007]

In view of the above problems, the present invention provides a thermoplastic resin foam having excellent ability to capture formaldehyde, ammonia, etc., reduced peculiar odor, and excellent appearance, and a foam thereof. The object is to provide a method for stable production.

[0008]

Means for Solving the Problems As a result of intensive studies on the cause of clogging of a screen breaker by paying attention to the reaction between a polyphenol compound and a deodorant, the present inventors I came to find a means.

That is, the present invention is (1) a foam made of a thermoplastic resin, characterized in that a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid, and a polyphenol compound are added. A thermoplastic resin foam, (2) a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid is added in an amount of 0.05 to 10% by weight, and a polyphenol compound is added in an amount of 0.01 to 20% by weight. The thermoplastic resin foam according to (1) above,
(3) The thermoplastic resin foam has a thickness of 0.5 to 10 mm,
Average bubble diameter 0.3 to 3 mm, apparent density 15 to 75
The thermoplastic resin foam according to the above (1) or (2), which is a polyolefin resin foam having a weight ratio of kg / m ³ , and (4) the polyphenol compound are represented by the following general formula (I). A thermoplastic resin foam according to any one of (1) to (3) above, which is a compound;

[0010]

[Chemical 3] (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 galloyro group represented by the following general formula (II).)

[0011]

[Chemical 4]

(5) Melt flow rate is 0.1 to 30
Polyethylene resin having a density of g / 10 minutes and a density of 940 kg / m ³ or less, a polyphenol compound, a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid,
Further foaming to a resin composition obtained by adding 0.01 to 20% by weight of a polyphenol compound and 0.05 to 10% by weight of a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid. A method for producing a thermoplastic resin foam, which comprises subjecting a foamable molten resin composition prepared by adding an agent to extrusion foaming.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION There is no limitation on the thermoplastic resin constituting the thermoplastic resin foam of the present invention (hereinafter referred to as foam), but in general, from the viewpoint of versatility and processability, a polyethylene resin is usually used. , Polypropylene-based resins, polystyrene-based resins are preferably used. Furthermore, since they are rich in flexibility and excellent in chemical resistance, it is possible to obtain an excellent foam as a material for construction and furniture. Polyolefin resins such as polyethylene resins and polypropylene resins are preferred. However, the present invention is not limited to these, and as the thermoplastic resin, for example, a polycarbonate resin, a polyamide resin, a polyester resin, or the like can be used.

The thermoplastic resin includes a cell regulator, an ultraviolet absorber, an infrared absorber, an infrared reflector, a flame retardant, a fluidity improver, a weathering agent, a colorant, a heat stabilizer, an antioxidant and a filler. You may add various additives, such as these, as needed.

Examples of the polystyrene resin constituting the thermoplastic resin include styrene homopolymers and copolymers, and the styrene monomer unit contained in the copolymer is at least 25% by weight, preferably 50% by weight. weight%
Or more, more preferably 70% by weight or more. Specifically, polystyrene, rubber-modified polystyrene, styrene-
Acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Examples thereof include a methyl acrylate copolymer, a styrene-ethyl acrylate copolymer, a styrene-maleic anhydride copolymer, and a polystyrene-polyphenylene ether copolymer. Further, the polystyrene-based resin also includes a mixture of the above-mentioned styrene homopolymer or copolymer with other polymer within the range of 40% by weight or less. Since the polystyrene-based resin is easy to foam and has excellent mechanical strength, it is possible to obtain an excellent foam as a building material having low density and excellent heat insulating properties.

[0016] Further, the polyester that constitutes the thermoplastic resin
As the ethylene resin, ethylene homopolymer, ethylene
Ethylene containing more than 60% by weight of monomer units
Examples thereof include high-density copolymers.
Ethylene, medium density polyethylene, low density polyethylene, straight
Chain low density polyethylene, ultra low density polyethylene, ethylene
A len-vinyl acetate copolymer and the like are preferable. In addition,
The ethylene resin is a homopolymer or copolymer of the above ethylene.
Other polymers were mixed in the range of 40% by weight or less
Including things. In addition, among the above polyethylene-based resins, the density is
940 kg / m ^ThreeThe following polyethylene resins are foamable
From the point, it is particularly preferable.

Examples of the polypropylene resin constituting the thermoplastic resin include propylene homopolymers and propylene copolymers containing propylene monomer units in an amount of 60% by weight or more. Examples of the copolymerization component include ethylene, butylene, and other α-olefins, and the carbon number of the α-olefin is 1
It is 2 or less, preferably 8 or less. Further, the polypropylene-based resin includes a mixture of the above-mentioned propylene homopolymer or copolymer with other polymers within the range of 40% by weight or less.

Among the polypropylene resins, the polypropylene resin supplied into the extruder is 230
It is preferable that the melt tension (MT) at 1.5 ° C. is 1.5 cN or more and the melt flow rate is 1 to 20 g / 10 minutes, and particularly the melt tension (MT) is further 3.0 cN, particularly 4.0 cN or more. More preferable. When such a polypropylene-based resin is used, it can be handled in the same manner as a thermoplastic resin such as a polystyrene-based resin or a polyethylene-based resin, which is relatively easy to form a foam having a thickness and an apparent density according to the purpose. Therefore, it is possible to eliminate the difficulty of forming a foam with a polypropylene resin.

The upper limit of the melt tension (MT) is about 30 cN from the viewpoint of foamability. Further, in the foam of the present invention obtained from a polypropylene resin satisfying the above MT, the MT measured from a test piece obtained by cutting out the foam and defoaming it by heat press is 1.5 to.
30cN, and further 2.0 to 25cN,
It is preferable because it has an excellent appearance and leads to a foamed molded product having a uniform thickness and apparent density.

Examples of other polymers to be mixed with the polyethylene resin, polypropylene resin, polystyrene resin include butadiene rubber, butadiene-styrene copolymer rubber, styrene-ethylene copolymer, styrene elastomer and the like. To be

The melt flow rate (MF) of the thermoplastic resin fed into the extruder to form the foam of the present invention.
R) is preferably 0.1 to 20 g / 10 minutes.
When the melt flow rate is less than 0.1 g / 10 minutes,
During extrusion foaming, the pressure inside the die attached to the tip of the extruder may rise excessively, which makes it difficult to form a foam. On the other hand, if the melt flow rate exceeds 20 g / 10 minutes, the flow is so good that the pressure required for extrusion foaming cannot be maintained, and there is a risk that it will be difficult to form a foam.

In the present specification, the melt tension (M
T) is a melt tension tester II manufactured by Toyo Seiki Co., Ltd., which is manufactured according to ASTM D1238.
Using a mold, a cylindrical orifice having a straight hole with a hole diameter of 2.095 mm and a length of 8 mm is used, and the resin temperature is 230 ° C. and the piston speed is 10 mm / min.

The procedure for measuring the melt tension will be described below. First, resin is extruded in a string shape from the orifice under the above conditions using the above apparatus, and the string piece is hung on a tension detecting pulley having a diameter of 45 mm, and then 5 rpm / sec (winding acceleration of the string piece: 1.3. It is wound with a winding roller having a diameter of 50 mm while gradually increasing the winding speed at a rate of about 10 ⁻² m / sec ² ).

Next, the winding speed is increased until the string-like object hung on the tension detecting pulley is broken, and the winding rate R (rpm) when the string-like object is broken is obtained. Then Rx
The string-like material was rewound at a constant winding speed of 0.7 (rpm), and the melt tension of the string-like material detected by the detector connected to the tension detection pulley was measured over time, and the longitudinal A graph with amplitude is obtained by plotting melt tension on the axis and time on the horizontal axis.
As the melt tension in this specification, the median value of the amplitude in the stable amplitude part is adopted. However, when the string-shaped material does not break even when the winding speed reaches 500 rpm, the melt tension of the string-shaped material is calculated from the graph obtained by winding the string-shaped material at a winding speed of 500 rpm. It should be noted that a rare peculiar amplitude value may be detected during the measurement of the melt tension over time, but such a peculiar amplitude value is ignored.

The melt flow rate (MFR) of the thermoplastic resin in this specification is JISK 7210 (197).
6), and polypropylene-based resin is the condition 14 in Table 1 of JIS K 7210 (1976).
According to JIS K 7210
According to the condition 8 of Table 1 of (1976), the polyethylene-based resin is the condition 4 of Table 1 of JIS K 7210 (1976).
According to JIS K 7210
It shall be measured under the condition 20 in Table 1 of (1976).

The open cell ratio of the foam of the present invention is 5% or more,
Further, it is preferably 10% or more, and particularly preferably 50% or more. When the open cell ratio is high, the foam film of the open cell structure portion formed outside and inside the foam is in direct contact with formaldehyde and the like, so that formaldehyde and the like can be captured inside the foam. Therefore, such a foam has far superior ability to trap formaldehyde and the like as compared with non-foam and foam having a closed cell structure.

That is, the excellent ability to trap formaldehyde and the like is due to the increase in the adsorption efficiency by increasing the surface area of the foam which is the adsorbent, the chemical adsorption ability with the polyphenol compound, and the above chemical adsorption ability. It is considered that the trapping ability is sustained and the effect of suppressing the release of adsorbed substances into the atmosphere is complicated by the complicated and complicated air passages formed by the open-cell structure of the foam.

In order to obtain a foam having an open cell ratio within the above range, for example, by adjusting the extrusion foaming temperature in the extrusion foaming method described later, a foam having an open cell structure with good appearance without shrinkage is obtained. be able to. Specifically, a foam having a high open cell ratio can be obtained by extrusion foaming at a temperature slightly higher than the extrusion foaming temperature condition for obtaining a foam having a closed cell structure.

Further, even if the foam has a closed cell structure,
Using the through-hole forming apparatus 1 shown in FIG. 3, using the needle roll 2 and the receiving roll 3 provided with the through-hole forming needle 4,
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 obtain the foamed body 6 having the open-cell structure in which the through hole 7 is formed.

The measurement of the open cell ratio in the present specification is A
According to STM D-2856-70 [1976 Recertification] (Procedure C), the procedure is as follows. The true volume Vx (cm ³ ) of the measurement sample is obtained using an air pycnometer, the apparent volume Va (cm ³ ) is obtained from the outer dimensions of the measurement sample, and the open cell rate (%) is calculated by the 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.

[0031]

## EQU1 ## Open cell rate (%) = {(Va-Vx) / (Va-W / ρ)} × 100 (1) In the formula (1), W is the weight (g) of the measurement sample, ρ Is the density (g / cm ³ ) of the base material forming the foam.

When the foam is a sheet, the measurement sample is
Cut a plurality of 40 mm long and 25 mm wide sheet-shaped samples and stack the cut-out samples to a thickness of about 25 m.
What is designated as m is used. Approximately 25 mm of test pieces should be stacked so that there are no gaps between them.
Thickness. If the foam is plate-shaped or long, the length is 40
mm, 25 mm in width, and 25 mm in thickness are used as test pieces. If a test piece of the above size cannot be cut out from the foam, cut out as many samples as possible and combine them to obtain a length of 40 m.
m, width 25 mm, thickness 25 mm.

A composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid, and a polyphenol compound are added to the foam of the present invention. The foam to which such a substance is added has an excellent ability to trap formaldehyde, ammonia and the like, and has a characteristic odor reduced.

In the foam of the present invention, the polyphenol compound is a polyethylene resin, a polyphenol compound, a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid (hereinafter also referred to as a deodorizing composition) in total. It is preferable that the content of the composition is 0.01 to 20% by weight, more preferably 0.1 to 10% by weight,
It is more preferable that the amount added is 0.1 to 5% by weight. If the addition amount of the polyphenol compound is too small, it may not be possible to obtain sufficient formaldehyde scavenging ability. If the amount of the polyphenol compound added is too large, it may be difficult to obtain a foamed product, and it may not be possible to obtain the effect commensurate with the content, resulting in an increase in cost.

In the foam of the present invention, the content of the deodorizing composition in the total composition of the polyethylene resin, the polyphenol compound and the deodorizing composition is 0.05-10.
It is preferable that it is added so as to be a weight%,
More preferably, it is added in an amount of 0.1 to 5% by weight. If the amount of the composition comprising the zinc compound, weakly alkaline inorganic substance and hydrous silicic acid added is too small, it may not be possible to obtain the effect of sufficiently reducing the odor during production and the odor of the foam. On the other hand, if the amount of the deodorant composition added is too large, it may be difficult to obtain a foamed product, and it may not be possible to obtain an effect commensurate with the content, and the cost will increase.

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

There are many kinds of polyphenol compounds in plants, most of them are flavonoid compounds, that is, flavones, flavonols, flavanones, flavanonols, isoflavones, anthocyanidins, leucocyanidins and flavanols. Exist as polymers, polyhydroxy derivatives, methylated products, glycosides, etc., and most of these compounds are THE HAND
BOOK OF NATURAL FLAVONOID
S (Volume 1, 2) Copyright 19
99 by JOHN WILEY & SONS,
Listed in LTD. In the present invention, those natural polyphenol compounds contained in plants are preferable, and among them, the compounds represented by the following general formula (I) are most preferable.

[0038]

[Chemical 5]

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 galloyl group represented by the following general formula (II). )

[0040]

[Chemical 6]

The compound represented by the general formula (I) has asymmetric carbon atoms at the 2- and 3-positions of the benzopyran ring. In the present invention, the isomers derived from these asymmetric carbon atoms are not limited. Absent.

Specific examples of the compound represented by the above general formula (I) include (-)-epicatechin ((-).
-Epicatechin: R1 and R in formula (I)
2 represents a hydroxyl group, R3 and R4 represent hydrogen atoms, and the configurations at the 2-position and 3-position represent 2R and 3R. ), (-)
-Catechin ((-)-catechin: In the formula (I), R1 and R2 represent a hydroxyl group, R3 and R4 represent hydrogen atoms, and the configurations at the 2- and 3-positions represent 2S and 3R), (+ ) -Catechin ((+)-catechi
n: In the formula (I), R1 and R2 represent a hydroxyl group, and R
3, R4 represents a hydrogen atom, and the configurations at the 2- and 3-positions represent 2R and 3S. ), (+)-Epicatechin ((+)-epicatechin: In the formula (I), R1 and R2 represent a hydroxyl group, R3 and R4 represent a hydrogen atom, and the configurations at the 2- and 3-positions are 2S and 3S. ), (−)-Epicatechin gallate ((−)-ep
icatechinglate: In the formula (I), R1 and R2 represent a hydroxyl group, R3 represents a hydrogen atom, and R
4 represents a galloyl group, and the configurations of 2- and 3-positions are 2
Represents R and 3R. ), (-)-Catechin gallate ((-)-catechin gallate: In the formula (I), R1 and R2 each represent a hydroxyl group, R3 represents a hydrogen atom, R4 represents a galloyl group, and stereochemistry at the 2- and 3-positions). The arrangement represents 2S and 3R.), (+)-Catechin gallate ((+)-catechin gallat)
e: In the formula (I), R1 and R2 represent a hydroxyl group, and R3
Represents a hydrogen atom, R4 represents a galloyl group, and the configurations at the 2- and 3-positions represent 2R and 3S. ), (+)-Epicatechin gallate ((+)-epicatechin
gallate: In the formula (I), R1 and R2 represent a hydroxyl group, R3 represents a hydrogen atom, R4 represents a galloyl group, and the configurations at the 2- and 3-positions represent 2S and 3S. ), (−)-Epigallocatechin ((−)-epig
allocatechin: R1 and R in formula (I)
2, R3 represents a hydroxyl group, R4 represents a hydrogen atom, and the configurations at the 2- and 3-positions represent 2R and 3R. ), (-)
-Gallocatechin ((-)-gallocatechi
n: In the formula (I), R1, R2, and R3 each represent a hydroxyl group, R4 represents a hydrogen atom, and the configurations at the 2- and 3-positions 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 configurations at the 2- and 3-positions represent 2R and 3S. .), (+)-Epigallocatechin ((+)-epig.
allocatechin: R1 and R in formula (I)
2, R3 represents a hydroxyl group, R4 represents a hydrogen atom, and the configurations at the 2- and 3-positions represent 2S and 3S. ), (-)
-Epigallocatechin gallate ((-)-epigal)
Octachin gallate: In the formula (I), R1, R2, and R3 represent a hydroxyl group, R4 represents a galloyl group, and the configurations at the 2- and 3-positions represent 2R and 3R. ), (-)-Gallocatechin gallate ((-)-ga
Llocatechin gallate: In the formula (I), R1, R2, and R3 represent a hydroxyl group, R4 represents a galloyl group, and the configurations at the 2- and 3-positions represent 2S and 3R. ), (+)-Gallocatechin gallate ((+)-g
allocatechin gallery: Formula (I)
In, R1, R2, and R3 represent a hydroxyl group, R4 represents a galloyl group, and the configurations at the 2- and 3-positions are 2R and 3S.
Represents ), (+)-Epigallocatechin gallate ((+)-epigallocatechin gal
late: In formula (I), R1, R2, and R3 represent a hydroxyl group, R4 represents a galloyl group, and the configurations at the 2- and 3-positions represent 2S and 3S. ), (-)-Epiafzelechin ((-)-epiafzelechin: Formula (I)
In, R1, R3, and R4 represent a hydrogen atom, R2 represents a hydroxyl group, and the configurations at the 2- and 3-positions represent 2R and 3R. ), (-)-Afzelequin ((-)-afzel
echin: In the formula (I), R1, R3, and R4 represent hydrogen atoms, R2 represents a hydroxyl group, and the configurations at the 2- and 3-positions 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 configurations at the 2- and 3-positions represent 2R and 3S. ), (+)-Epiafzerekin ((+)-epia
fzelechin: R1, R3, R in formula (I)
4 represents a hydrogen atom, R2 represents a hydroxyl group, and the configurations at the 2- and 3-positions represent 2S and 3S. ), (-)-Epiafzelequingallate ((-)-epiafzelec
Hinglate: In the formula (I), R1 and R3 are hydrogen atoms, R2 is a hydroxyl group, R4 is a galloyl group, and the configurations at the 2- and 3-positions are 2R and 3R. ), (-)-Afzelequin gallate ((-)-af
zelechinglate: R in formula (I)
1, R3 is a hydrogen atom, R2 is a hydroxyl group, R4 is a galloyl group, and the configurations at the 2- and 3-positions are 2S and 3R.
Represents ), (+)-Afzelequin gallate ((+)-
afzelechinglate: In the formula (I), R1 and R3 are hydrogen atoms, R2 is a hydroxyl group, R4 is a galloyl group, and the configurations at the 2- and 3-positions are 2R,
Represents 3S. ), (+)-Epiafzelequingallate ((+)-epiafzelechingingallat)
e: In the formula (I), R1 and R3 are hydrogen atoms, R2 is a hydroxyl group, R4 is a galloyl group, and the configurations at the 2- and 3-positions are 2S and 3S. )and so on. Many of these compounds are used in tea plants (Camellia sinen).
sis) leaves and stems, and green tea processed from them,
It is contained in black tea, oolong tea, puir tea, etc.

When a plant-derived polyphenol compound is used in the present invention, the kind and part of the plant used as a raw material are not particularly limited, but examples thereof include tea trees, persimmons, chestnuts, cacao, quebrathio, mimosa, apples, citrus fruits, grapes and blueberries. And leaves such as rosemary, stem, xylem, bark,
Roots, fruits and seeds, or processed products thereof can be appropriately selected and used as the raw material of the polyphenol compound.
These raw materials can be used as they are in the present invention by pulverizing them to an appropriate size, but usually, the polyphenol compound is extracted from these raw materials by further using water, hot water, a water-containing organic solvent and an organic solvent. To 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 Publications No. 1-44234 and 2-1247.
No. 4, JP-A-2-22755, JP-A-4-205
No. 89, No. 5-260907, No. 8-109.
Specific examples are described in Japanese Patent No. 178, etc., and the above method can be carried out also when a polyphenol compound is obtained from a plant other than tea.

On the other hand, the individual deodorizing components used in the deodorizing composition added to the foam of the present invention are all known compounds per se.

As the zinc compound constituting the deodorizing composition used in the present invention, various zinc compounds, for example, inorganic zinc compounds such as zinc oxide, zinc sulfate, zinc chloride, zinc phosphate, zinc nitrate, zinc carbonate, etc. , Zinc acetate, zinc oxalate,
Organic zinc salts such as zinc citrate, zinc fumarate and zinc formate can be used, but zinc white (zinc oxide) is particularly preferable. When these zinc compounds are contained in the deodorizing composition, the effect of removing the odor of sulfides such as hydrogen sulfide can be obtained.

As the weakly alkaline substance constituting the deodorizing composition used in the present invention, oxides or hydroxides of alkaline earth metals such as magnesium, calcium, barium and strontium are most suitable, and other Valide metal hydroxides, alkali metal carbonates, alkali metal acetates, ammonium carbonate, etc. are also effective. Particularly preferred is magnesium hydroxide. By containing these alkaline substances in the deodorizing composition, in addition to the formaldehyde scavenging ability, the effect of removing the acidic odor by the neutralization reaction can be obtained.

As the hydrous silicic acid constituting the deodorizing composition used in the present invention, particles having a large number of silanol groups on the surface of silica fine particles represented by the chemical formula SiO ₂ .nH ₂ O are aggregated as secondary particles. Preferred are those mentioned above. Such hydrous silicic acid is an aggregate of ultrafine particle hydrous silicic acid obtained by reacting sodium silicate with a mineral acid, and has a large number of voids. Such hydrous silicic acid is, for example,
Product name P-801, P-802, P from Mizusawa Chemical Co., Ltd.
-526, P-527, P-603, P-604, P-
554A, P-73, P-78A, P-78D, P-7
8F, P-707, P-740, P-752, P-5
0, P-766, C-1, S-0, NP-8, P-80
2Y, P-832, P-87, P-363, C-00
2, commercially available as C-402, C-484, etc.,
It can be used in the present invention.

As the hydrous silicic acid constituting the deodorizing composition of the present invention, minerals such as zeolite and sepiolite can also be mentioned.

When these hydrous silicic acids are added to a foam containing a polyphenol compound, many voids present in the hydrous silicic acid not only significantly affect the uptake of malodorous components such as formaldehyde and acetaldehyde, but also polyphenols. The active chemical reaction between the compound and the weakly alkaline substance is suppressed, and the function of the hydrous silicic acid as a buffer substance is exhibited.

In the deodorizing composition added to the foam of the present invention, the deodorizing property can be adjusted by the use ratio of the zinc compound, the weakly alkaline substance and the hydrous silicic acid. The use ratio of the zinc compound, the weakly alkaline substance and the hydrous silicic acid is preferably 10 to 50 parts by weight of the zinc compound and 10 to 500 parts by weight of the silicic acid hydrate with respect to 100 parts by weight of the weakly alkaline substance. 20 to 30 parts by weight of zinc compound and 50 to 4 of hydrous silicic acid, based on parts by weight.
A range of 00 parts by weight is more preferable. With such combinations and blending ratios, the deodorizing object of the present invention is best achieved.

When the foam of the present invention is produced, the deodorizing composition may be simply mixed with the thermoplastic resin, or the deodorizing composition may be melt-kneaded and granulated into pellets or the like. Good. Further, it may be added in a masterbatch containing a high concentration (for example, a concentration of 10 to 50% by weight) of the deodorant composition, and the masterbatch is diluted with a thermoplastic resin containing no deodorant composition. May be added.

In producing the foam of the present invention, the polyphenol compound may be simply mixed with the thermoplastic resin. However, like the method of adding the deodorizing composition to the thermoplastic resin, pellets or the like may be added. Granulated product, masterbatch, or masterbatch diluted product may be added. Further, the polyphenol compound and the deodorizing composition can be added to the thermoplastic resin in a masterbatch containing both.

In the foam of the present invention, since the polyphenol compound and the deodorizing composition are added to the thermoplastic resin as described above, in addition to the effect of scavenging formaldehyde etc. by the addition of the polyphenol compound, the polyphenol compound is added. The odor peculiar to the added foam is reduced. Further, also during the production of the foam, the generation of odor due to the added polyphenol compound is reduced.
Furthermore, since the generation of granular lumps is suppressed, the work of replacing the mesh during foam production is reduced, and the granular lumps that cannot be completely removed by the mesh are not mixed into the foam, and the surface condition of the foam is reduced. Can be prevented from worsening.

The granular lumps mixed in the conventional foam are considered to be crystallized products generated by the reaction of the deodorant and the polyphenol compound, and in the present invention, they are contained in the deodorant composition as described above. It is considered that hydrous silicic acid acts as a buffer substance and suppresses the generation of granular lumps.

Further, the foam of the present invention also has an effect of improving the trapping rate of formaldehyde as compared with the foam to which only the polyphenol compound is added. It is considered that such an effect is caused by the fact that the deodorizing composition contains hydrous silicic acid, whereby the alkalinity of the foam becomes stronger and the binding reaction rate between formaldehyde and the polyphenol compound becomes faster.

The foam of the present invention has a thickness of 0.5 to 10 m.
m, average bubble diameter 0.3 to 3 mm, apparent density 15 to
It is preferably formed as a sheet-like foam having a weight of 75 kg / m ³ . The foam having such a structure is used, for example, as a tatami mat component to be inserted between the tatami mat and the core material of the tatami mat, a closet, a closet, an underlay material for a cupboard or a shoe box, or a bag after being bag-formed. , Formaldehyde and ammonia in the air can be effectively captured. In particular, when an olefin resin, particularly a polyethylene resin, is used as the base resin, it is possible to obtain an inexpensive scavenging material such as formaldehyde while having excellent physical properties such as mechanical strength, flexibility and toughness.

In the above structure, if the thickness is less than 0.5 mm, the mechanical strength may be insufficient and the mechanical strength may be insufficient. If the thickness exceeds 10 mm, the tatami mat is not suitable for some purposes such as a tatami mat component. It will be Average bubble diameter is 0.3m
When it is less than m, unevenness may occur on the surface of the sheet, resulting in poor smoothness, and when the average cell diameter exceeds 3 mm, appearance and touch may be deteriorated. If the apparent density is less than 15 kg / m ³ , the expansion ratio may be too large and the cell membrane may be thin, resulting in a decrease in mechanical strength. If the apparent density exceeds 75 kg / m ³ , the flexibility may be insufficient. It may be inconvenient to use as a component of a tatami mat, an underlay material for a closet, and the like.

The foam of the present invention has a thickness of 10 to 70.
mm, average bubble diameter 0.2-5 mm, apparent density 20
It is also preferable to form it as a plate having a cross-sectional area of 25 cm ² or more in a vertical direction of ˜100 kg / m ³ . The foam having such a structure is suitable as a building material having both heat insulating properties and formaldehyde scavenging ability. When used for such an application, using a polyethylene-based resin as the base resin has
Preference is given to flexibility and price balance, and polystyrene resin is preferable when compressive strength and rigidity are required.

In the above structure, if the thickness is less than 10 mm, the heat insulating property may be insufficient, and if the thickness exceeds 70 mm, it may be too thick and the efficiency of trapping formaldehyde and the like inside the foam may decrease. Therefore, there is a possibility that the formaldehyde trapping ability and the like commensurate with the addition amount of the polyphenol compound cannot be obtained. Average bubble diameter is 0.2m
If it is less than m, the bubble film becomes thin, so the compressive strength may decrease depending on the application, and if the average bubble diameter exceeds 5 mm, the heat insulating property may deteriorate. Apparent density is 20
If it is less than kg / m ³ , the bubble film becomes thin, so the mechanical strength may decrease depending on the application, and the apparent density is 1
If it exceeds 00 kg / m ³ , the heat insulating property may deteriorate.

The foam of the present invention has an apparent density of 20.
It is also preferable to form a rod-shaped long foam or a tubular long foam having continuous cracks in the longitudinal direction, which has a cross-sectional area of 5 cm ² or more in the vertical direction of ˜100 kg / m ³ . The long foam having such a structure can be used as a joint material, and the long tubular foam can be used, for example, to spread cracks in the long foam on pillars, railings, doors, windows, etc. of a new house. Then, it can be suitably used as a protective material for a building or the like that is installed and protected when a household property is brought in. When used for the above-mentioned applications, it is preferable to use a polyethylene resin as the base resin from the viewpoints of mechanical properties, flexibility and cushioning properties.

In this specification, the apparent density of the foam is a value measured according to JIS K7222-1985. Further, the thickness of the foam is JIS K722
It is a value measured based on the measurement method of the thickness of the test piece of 2-1985.

The method of measuring the average cell diameter of the foam in this specification is as follows. The average cell diameter in the thickness direction (a) and the average cell diameter in the width direction (b) are the vertical cross section of the foam (the vertical cross section orthogonal to the extrusion direction of the foam).
For the average cell diameter (c) in the extrusion direction, use a microscope or the like for the vertical section of the foam in the extrusion direction (the vertical section that bisects the foam in the width direction and is orthogonal to the width direction of the foam plate). On the screen or monitor, draw a straight line in the direction to be measured on the projected image, count the number of bubbles crossing the straight line, and measure the length of the straight line (however, this length is enlarged and projected. The average bubble diameter in each direction is obtained by dividing the length of the straight line on the projected image, not the length of the straight line on the projected image, taking into account the magnification of the projected image.) By the number of bubbles counted. .

However, the average bubble diameter (a) in the thickness direction is measured by drawing straight lines extending over the entire thickness in the thickness direction at a total of three locations in the center and both ends of the cross section perpendicular to the width direction and the length of each straight line. The average diameter of the bubbles existing on each straight line (the length of the straight line / the number of bubbles crossing the straight line) is calculated from the number of bubbles crossing
The calculated average value of the average diameters of the three locations is defined as the average bubble diameter (a) in the thickness direction.

Further, the average cell diameter (b) in the width direction is 3000 μm at a position where the thickness of the foam is bisected at a total of three positions, that is, the central portion and both end portions of the cross section perpendicular to the width direction.
A straight line of m is drawn in the width direction, and the average diameter of the bubbles present on each line from the straight line having a length of 3000 μm and (the number of bubbles crossing the straight line-1) (3000 μm / (the number of bubbles crossing the straight line) -1)) is obtained, and the arithmetic average value of the obtained average diameters of the three locations is defined as the average bubble diameter (b) in the width direction.

Further, the average cell diameter (c) in the extrusion direction has a length of 3000 at a position where the thickness of the foam is bisected in a total of 3 positions, that is, the central portion and both end portions of the vertical cross section.
A straight line of μm is drawn in the longitudinal direction, and from the line of 3000 μm in length and (the number of bubbles crossing the line-1), the average diameter of the bubbles present on each line (3000 μm / (the number of bubbles crossing the straight line -1)) is obtained, and the arithmetic average value of the obtained average diameters of 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 taken as the average cell diameter of the foam.

Hereinafter, preferred production examples of the foam of the present invention will be described. The foam of the present invention is obtained by heating and kneading a thermoplastic resin, (i) a polyphenol compound, (ii) a zinc compound, a composition comprising a weakly alkaline inorganic substance and hydrous silicic acid in an extruder, and further adding a physical foaming agent. It can be obtained by press-kneading into an extruder to obtain a foamable molten resin composition, and then extruding the foamable molten resin composition from a die attached to the tip of the extruder to foam.

Examples of the above-mentioned physical foaming agent used for obtaining the foam of the present invention include propane, n-butane, i-butane, industrial butane, pentane, aliphatic hydrocarbons such as hexane, cyclopentane, cyclohexane and the like. Halogenated hydrocarbons such as cycloaliphatic hydrocarbons, 1,1-difluoroethane, 1,1-difluoro-1-chloroethane, 1,1,1,2-tetrafluoroethane, methyl chloride, ethyl chloride and methylene chloride ,carbon dioxide gas,
Inorganic gas such as nitrogen, water and a mixture thereof may be used. Further, in the present invention, azodicarbonamide,
A chemical foaming agent such as dinitrosopentamethylenetetramine, azobisisobutyronitrile or sodium bicarbonate can also be used in combination.

However, it is preferable to use those which do not contain chlorofluorocarbon which may adversely affect the environment such as destruction of the ozone layer. In addition, since an organic physical foaming agent is used, it is possible to obtain one having a small apparent density.
It is preferable to use a physical foaming agent containing at least wt%.

The apparent density of the foam of the present invention is as follows:
Since it changes depending on the type of foaming agent, the amount of foaming agent added, etc., it is necessary to select the amount of foaming agent added to obtain the desired apparent density depending on the type of foaming agent and the type of base resin. .

In the formation of the foamed product of the present invention, a cell regulator is used together with the physical foaming agent. Examples of the air bubble modifier 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.

As described above, the addition amount of the composition (i) polyphenol compound, (ii) zinc compound, weakly alkaline inorganic substance and hydrous silicic acid added to the thermoplastic resin is 0.01 -20% by weight, preferably 0.
1 to 10% by weight, more preferably 0.1 to 5% by weight,
(Ii) is added 0.05 to 10% by weight, preferably 0.1
~ 5% by weight.

Examples of the die used for extrusion foaming the foam of the present invention include an annular die, a flat die and a profile die. When using an annular die, the expandable molten resin composition is extruded under atmospheric pressure through an annular die provided at the tip of an extruder to foam into a tubular shape, and the tubular foam is cut out along the extrusion direction. For example, a foamed sheet can be obtained. When a flat die is used, a plate-shaped foam can be obtained, and when a deformed die is used, foams having various different cross-sectional shapes can be obtained.

The thickness is 10 to 70 mm, the average bubble diameter is 0.2 to 5 mm, and the apparent density is 20 to 100 kg / m.
³ , a foam having an area of a cross section perpendicular to the longitudinal direction of 25 cm ² or more, or an apparent density of 20 to 100 kg /
In the case of producing a rod-shaped long foam or a cylindrical long foam having continuous cracks in the longitudinal direction, having a cross-sectional area of 5 cm ² or more in the vertical direction with respect to m ³ , between the extruder and the die. You may install an accumulator. By installing an accumulator, the discharge speed can be dramatically increased, so that the foam of the present invention having a high expansion ratio and a high thickness can be easily obtained.

[0076]

EXAMPLES The present invention will be described in more detail with reference to examples.

In Table 1, used in Examples and Comparative Examples,
The component compositions of two kinds of polyphenol compounds consisting of green tea extract are shown in Table 2, the component composition of the deodorant composition masterbatch added in the example of the present invention and the component composition of the deodorant masterbatch added in the comparative example, respectively. Show.

[0078]

[Table 1]

[0079]

[Table 2]

Example 1 MFR was 4.5 g / 10 minutes and density was 0.916 kg / m.
³ polyethylene resin (84.3 parts by weight) and 5 parts of sodium citrate to 100 parts by weight of polyethylene resin.
A cell regulator masterbatch (2.0 parts by weight) containing 1 part by weight and 10 parts by weight of talc, and a polyethylene resin 1
An anti-shrinking agent masterbatch (1 part by weight of 12 parts by weight of monostearic acid glyceride to 100 parts by weight) (1
1.4 parts by weight) and a deodorant composition masterbatch D (1.
3 parts by weight) and green tea extract B (1.0 parts by weight) are fed to an extruder, heated and kneaded to form a molten resin, and isobutane and normal butane are used as physical blowing agents. A mixed foaming agent (9.0 parts by weight with respect to 100 parts by weight of the mixed raw material) mixed in a weight ratio of 3 to 7 was pressed into the molten resin in the extruder and further kneaded to obtain a 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-shaped foam. The obtained sheet-shaped foam,
The through holes were formed by passing through a through hole forming device having a large number of through hole forming needles provided on the roll.

Example 2 MFR was 4.5 g / 10 min and density was 0.916 kg / m.
³ polyethylene resin (83.6 parts by weight), the cell regulator masterbatch (2.5 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the deodorizing composition masterbatch E ( 1.5 parts by weight) and green tea extract B
(1.0 parts by weight) was used, and 9.0 parts by weight of the mixed foaming agent with respect to 100 parts by weight of the mixed raw material was pressed into the molten resin in the extruder. Similarly, a sheet-shaped foam was manufactured.

Example 3 MFR of 4.5 g / 10 minutes and density of 0.916 kg / m
³ polyethylene resin (84.1 parts by weight), the cell regulator masterbatch (2.2 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the deodorizing composition masterbatch F ( 1.3 parts by weight) and green tea extract B
(1.0 parts by weight) was used, and 9.0 parts by weight of the mixed foaming agent with respect to 100 parts by weight of the mixed raw material was pressed into the molten resin in the extruder. Similarly, a sheet-shaped foam was manufactured.

Example 4 MFR of 4.5 g / 10 minutes and density of 0.916 kg / m
³ polyethylene resin (75.8 parts by weight), the cell regulator masterbatch (0.3 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the deodorizing composition masterbatch E ( 7.5 parts by weight) and green tea extract B
(5.0 parts by weight) was used as a raw material, and 9.0 parts by weight of the mixed foaming agent with respect to 100 parts by weight of the mixed raw material was pressed into the molten resin in the extruder. Similarly, a sheet-shaped foam was manufactured.

Comparative Example 1 MFR was 4.5 g / 10 min, and density was 0.916 kg / m.
³ polyethylene resin (84.4 parts by weight), the cell regulator masterbatch (3.2 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the green tea extract B (1. Example 1 except that a mixed raw material was mixed with 100 parts by weight of the mixed raw material and 9.0 parts by weight of the mixed foaming agent was pressed into the molten resin in the extruder.
A sheet-shaped foam was produced in the same manner as in.

Comparative Example 2 MFR was 4.5 g / 10 minutes and density was 0.916 kg / m.
³ polyethylene resin (84.1 parts by weight), the cell regulator masterbatch (2.3 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the deodorant masterbatch C (1 .2 parts by weight) and green tea extract B (1.
0 parts by weight) and the above mixed raw material 10
A sheet-shaped foam was produced in the same manner as in Example 1 except that 9.0 parts by weight of the mixed foaming agent was pressed into the molten resin in the extruder with respect to 0 parts by weight.

Comparative Example 3 MFR was 4.5 g / 10 minutes and density was 0.916 kg / m.
³ polyethylene resin (84.8 parts by weight), the cell regulator masterbatch (2.5 parts by weight), the shrinkage inhibitor masterbatch (11.4 parts by weight), and the deodorant masterbatch C (0 .3 parts by weight) and green tea extract B (1.
0 parts by weight) and the above mixed raw material 10
A sheet-shaped foam was produced in the same manner as in Example 1 except that 9.0 parts by weight of the mixed foaming agent was pressed into the molten resin in the extruder with respect to 0 parts by weight.

Table 3 shows the open cell ratio, apparent density, thickness, width and average cell diameter of the foams obtained in Examples 1 to 4 and Comparative Examples 1 to 3.

[0088]

[Table 3]

Example 5 A polypropylene resin (87.1 parts by weight) having an MFR of 3 g / 10 minutes and a melt tension of 20 gf, sodium citrate (0.1 parts by weight) and talc (0.
3 parts by weight), green tea extract A (5.0 parts by weight), and deodorant composition masterbatch E (7.5 parts by weight) were fed to an extruder, heated and kneaded. After forming the molten resin, isobutane (the above mixed raw material 10
(8 parts by weight with respect to 0 parts by weight) was press-fitted into the molten resin in the extruder and further kneaded to obtain a foamable molten resin mixture, and then 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-shaped foam. Through holes were formed in the obtained sheet-like foam through the apparatus shown in FIG.

Comparative Example 4 Polypropylene resin (94.6 parts by weight) having an MFR of 3 g / 10 minutes and a melt tension of 20 gf, sodium citrate (0.1 parts by weight) and talc (0.
3 parts by weight) and green tea extract A (5.0 parts by weight) were used as the raw materials, and the sheet was prepared in the same manner as in Example 5 except that the deodorizing composition masterbatch E (7.5 parts by weight) was not added. -Shaped foam was manufactured, and through holes were formed in the sheet-shaped foam obtained in the same manner as in Example 5.

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

[0092]

[Table 4]

[0093]

[Table 5]

The odors in Table 5 were evaluated according to the following criteria. The odor was an odor like roasted tea, a sweet odor like heated sugar, and an acid odor like a nose. ⊚: Almost no odor was perceived during production, and no odor was perceived from the resulting foam. ◯: Some odor is felt during production, but no odor is felt from the obtained foam. Δ: There is a considerable odor during production, and the obtained foam has a slight odor.

The evaluation of stability during production in Table 5 was carried out according to the following criteria. ⊚: Even if the foam is continuously produced for 24 hours or more, the pressure increase of the extruder due to the clogging of the mesh is not observed, and the foam can be produced under stable conditions. ◯: Mesh clogging occurs in 6 to 12 hours after continuously producing a foamed product. The foam can be produced under stable conditions by replacing the mesh when the pressure of the extruder starts to rise. Δ: Mesh clogging occurs in less than 6 hours after continuously producing foam. Frequent replacement of mesh during manufacturing,
Manufacturing is difficult under stable conditions.

The mesh is a wire mesh attached to the resin flow path at the connecting portion between the extruder and the die, and is for removing impurities and foreign substances in the molten resin.
In Examples and Comparative Examples, SUS-304 mesh flat tatami woven wire mesh 0.57 / 0.43 × 10/60 mesh (manufactured by Taiyo Wire Mesh Co., Ltd.)
Was used by stacking 3 sheets.

The foam plates obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to formaldehyde concentration test and ammonia concentration test. The results are shown in Table 5.

[0098]

[Table 6]

The formaldehyde absorption test was conducted as follows. As shown in FIG. 1, the desiccator 11 having an inner diameter of 240 mm has an inner diameter of 90 ml in which 300 ml of distilled water is put at the bottom of the desiccator 11.
The mm crystal dish 12 was placed, and the middle plate 13 was placed thereon.
On the middle plate 13, a foam body 14 to be tested and 0.1
Filter paper 15 onto which 1.0 ml of formaldehyde solution was dropped
Was placed, the lid 16 was placed, and the container was left in a constant temperature and humidity chamber at 20 ° C. and RH 65%. After a lapse of a predetermined time, the concentration of formaldehyde dissolved in distilled water in the crystal dish 12 was measured by the acetylacetone method to determine the amount of formaldehyde absorbed. In addition, the formaldehyde absorption capacity of the test object was confirmed by using the case where the same test was conducted without putting the foamed body in the desiccator as a blank. The foam 14 is 100 mm long.
Ten pieces having a width of 150 mm were used.

The ammonia deodorizing test was conducted as follows. As shown in FIG. 2, 1000 ml wide-mouthed reagent bottle 21
The foamed body 22 was put in and the filter paper 23 was put on it. After the mouth of the wide-mouthed reagent bottle 21 was sealed with an aluminum foil 24, a needle (not shown) of a microsyringe was pierced into the aluminum foil 24 and 10 μl of a 5% ammonia solution was added.
Was dropped on the filter paper 23. Immediately remove the pinhole 25 of the aluminum foil 24 with the needle by the vinyl tape 26
And closed at room temperature (25 ° C). After a lapse of a predetermined time, the ammonia gas concentration in the head space 27 was measured using a gas detector tube. Further, the ammonia deodorizing ability of the test object was confirmed by using the case where the same test was conducted without putting the foamed product in the bottle as a blank. The foam 22 has a length of 100.
Three sheets having a size of mm × width 150 mm were used.

[0101]

The thermoplastic resin foam of the present invention, having a polyphenol compound added thereto, has the ability to trap formaldehyde and ammonia. Further, since a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid is added as a deodorant treated to inhibit the reaction with the polyphenol compound, almost no odor is felt during production. No odor is felt from the foam obtained while maintaining the ability to trap formaldehyde and ammonia. Further, deterioration of physical properties and appearance due to inclusion of a crystallized product in the foam is also suppressed. Further, the foam of the present invention has further improved formaldehyde scavenging ability as compared with the foam containing only the polyphenol compound.

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

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

In the present invention, when the thickness, the average cell diameter, and the apparent density are formed as a sheet-like foam within a specific range, it is excellent as a tatami mat constituent member, a closet or a closet underlay material, and the like. Further, in the present invention, the thickness,
When the average foam diameter, the apparent density, and the area of the vertical cross section with respect 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 insulating properties and formaldehyde trapping ability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method for measuring formaldehyde concentration.

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

FIG. 3 is a view showing an example of a through hole forming device.

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 591039137             Mitsui Norin Co., Ltd.             3-2-11 Nishi-Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Seiji Takahashi             2-1-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Stock market             Company JSP (72) Inventor Yoshihiko Iijima             1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large             Within Nissei Chemical Co., Ltd. (72) Inventor Mikio Saki             1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large             Within Nissei Chemical Co., Ltd. (72) Inventor Hiroshi Hojo             223-1 Miyahara, Fujieda City, Shizuoka Prefecture             Central Research Laboratory, Kuno Co., Ltd. (72) Inventor Kazuki Kageyama             3-2-11 Nishishinjuku, Shinjuku-ku, Tokyo Mitsui Norin             Within the corporation F-term (reference) 4F074 AA08D AA12A AA13A AA17                       AA18 AA19 AA20 AA21 AA21A                       AA22 AA22A AA24 AA26A                       AA32 AA33 AA33A AA33B                       AA33D AA47A AA48A AA49A                       AA52 AA52A AA77B AB05                       AC08 AC11 AC17 AC19 AC21                       AC24 AC25 AC28 AC30 AC31                       AC32 AD10 AD12 AG19 AG20                       BA03 BA13 BA14 BA16 BA32                       BA33 BA34 BA35 BA36 BA37                       BA38 BA39 BA40 BA44 BA45                       BA47 BA53 BC12 BC13 CA22                       CB53 DA02 DA03 DA13 DA23                       DA32 DA37 DA50 DA57 DA58                 4J002 BB051 BB061 BB091 BB121                       BB141 BC021 BC041 BC051                       BC061 BC071 BH011 BN141                       BN151 DD076 DE066 DE076                       DE086 DE096 DE106 DE246                       DF006 DF036 DG046 DH036                       DJ016 EG046 EJ016 FD206                       FD320 GL00

Claims (5)

[Claims] 1. A foam comprising a thermoplastic resin, comprising:
A thermoplastic resin foam comprising a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid, and a polyphenol compound. 2. A composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid in an amount of 0.05 to 10% by weight and a polyphenol compound in an amount of 0.01 to 20% by weight. 1. The thermoplastic resin foam according to 1. 3. The thermoplastic resin foam has a thickness of 0.5 to 1.
0 mm, average bubble diameter 0.3 to 3 mm, apparent density 1
The thermoplastic resin foam according to claim 1 or 2, which is a polyolefin resin foam having a weight of 5 to 75 kg / m ³ . 4. The thermoplastic resin foam according to claim 1, wherein the polyphenol compound is a compound represented by the following general formula (I). [Chemical 1] (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 galloyro group represented by the following general formula (II).) 2] 5. A melt flow rate of 0.1 to 30 g /
10 minutes, a polyethylene resin having a density of 940 kg / m ³ or less, a polyphenol compound, a composition comprising a zinc compound, a weakly alkaline inorganic substance and hydrous silicic acid, 0.01 to 20% by weight of the polyphenol compound, and zinc. A foamable molten resin composition prepared by further adding a foaming agent to a resin composition obtained by adding a composition comprising a compound, a weakly alkaline inorganic substance and hydrous silicic acid so as to be contained in an amount of 0.05 to 10% by weight. A method for producing a thermoplastic resin foam, comprising extruding and foaming a product.