JP2000239342A - Production of hydrophilic open-cell polyisocyanurate foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject foam which is a complete open-cell foam capable of instantaneously absorbing and retaining water and having a specific foam density useful for a dew condensation preventing material, etc., in the interior of a house by reacting a specific polyisocyanate with a specified hydroxy compound, etc. SOLUTION: This foam is produced by reacting (A) an aromatic polyisocyanate with (B) a hydroxy compound comprising a polyether, etc., having >=1.0 average number of functional groups and containing >=20 wt.% of oxyethylene, (C) a silicone-based foam stabilizer which is a polysiloxane- polyoxyalkylene copolymer in which the end of the polyoxyalkylene polyether is capped with other compounds without having active hydrogen and the polyoxyalkylene contains >=30 wt.% of the polyoxyethylene and (D) a special additive, etc., which is a polyoxyalkylene derivative without having the active hydrogen in an amount of >=10 pts.wt. based on 100 pts.wt. of the component B. The resultant foam has 8-100 kg/m3 foam density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydrophilic open-celled polyisocyanurate foam.
More specifically, a hydrophilic continuous material that exhibits excellent properties as a dew-prevention material inside a house, a humidity absorption / release adjustment material, a waste ink absorption material for inkjet printers, a vacuum panel insulation material for refrigerators, a shock absorption material, etc. A foamed polyisocyanurate foam is provided.

[0002]

2. Description of the Related Art A method for producing an open-celled polyisocyanurate foam is known, and is disclosed, for example, in JP-A-8-31933.
0 shows a method for producing an open-celled polyisocyanurate foam. Japanese Patent Application Laid-Open No. 8-319330 discloses a method for producing an open-cell polyisocyanurate foam using a terminal hydroxyl-containing prepolymer of a specific polyol and a polyisocyanate. It was reduced and somewhat increased open cell rate to improve dimensional stability, far from open cell foam reaching 100%.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a hydrophilic open-celled polyisocyanurate foam which completely reaches 100%. Another object of the present invention is to provide a hydrophilic open-cell polyisocyanurate foam which readily absorbs water. It is another object of the present invention to provide a hydrophilic open cell polyisocyanurate foam that can retain absorbed water. It is another object of the present invention to provide a hydrophilic open cell polyisocyanurate foam whose compressive crush strength is approximately constant from 10% to 60%.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a polyisocyanate, a hydroxy compound, water and / or other foaming agents, a catalyst, a silicone-based foam stabilizer, a special additive, and if necessary, other ionic surfactants. In producing a foam from the polyisocyanurate, etc., 1) a polyisocyanate is an aromatic polyisocyanate, and 2) a hydroxy compound having an average number of functional groups of 1.0 or more and an oxyethylene content of 20% by weight or more and / or A hydroxy compound consisting of a polyester polyol, and 3) a catalyst using at least an isocyanurate-based catalyst, and 4) a silicone-based foam stabilizer being a polysiloxane-polyoxyalkylene copolymer, and a polyoxyalkylene polyether end. Has a structure capped with another compound having no active hydrogen, In addition, the polyoxyalkylene has a silicone-based foam stabilizer containing oxyethylene in an amount of 30% by weight or more, and 5) the special additive is a polyoxyalkylene derivative having no active hydrogen, and 6) 100 parts by weight of the hydroxy compound. By using the special additive in an amount of 10 parts by weight or more, the hydrophilic open-cell polyisocyanurate foam having a density of 8 to 100 kg / m ³ of the present invention can be produced. In carrying out the present invention, the silicone-based foam stabilizer is a polysiloxane-polyoxyalkylene copolymer,
The polyoxyalkylene polyether ends are C ₁ -C
_{It has 4} alkoxy groups or acyloxy groups. Claim 3 uses an anionic surfactant in combination with the present invention. According to a fourth aspect of the present invention, a water-absorbing resin is used in combination with the present invention.

The present invention will be described in more detail for carrying out the present invention. As the aromatic polyisocyanate used in the present invention, for example, polymethylene polyphenylene polyisocyanate, 4,4′-diphenylmethane diisocyanate, crude polymethylene polyphenylene polyisocyanate,
2,4′-diphenylmethane diisocyanate, 2,
There are 2′-diphenylmethane diisocyanate, 2,4 tolylene diisocyanate, 2,6 tolylene diisocyanate, 1,5 naphthalene diisocyanate and the like. The reason why the polyisocyanate is limited to the aromatic polyisocyanate in the present invention is that a good polyisocyanurate foam can be obtained, and sufficient reactivity cannot be obtained with an aliphatic isocyanate or an alicyclic isocyanate. This is because a highly hydrophilic open-cell polyisocyanurate foam cannot be obtained. Among these polyisocyanates, polymethylene polyphenylene polyisocyanate, 4,4'-diphenylmethane diisocyanate, and crude polymethylene polyphenylene polyisocyanate (crude MDI) are particularly preferred in view of foam reactivity and internal scorch. These polyisocyanates may be used alone or carbodiimide-modified and / or
Alternatively, various modifications such as urethane modification and / or urea modification and / or allophanate modification and / or isocyanurate modification can be used.

The hydroxy compound used in the present invention is a hydroxy compound and / or polyester polyol having an average number of functional groups of at least 1.0 and an oxyethylene content of at least 20% by weight. The former preferably has an average number of functional groups of 1.0 to 5.0 and a number average molecular weight of 20,000 or less. Particularly preferred hydroxy compounds have an average number of functional groups of 1.0 to 3.5 and a molecular weight of 500 to 100.
00, and the oxyethylene content is 50 to 90% by weight.
It is. When the oxyethylene content is 90% by weight or more, crystallization occurs at room temperature and it is difficult to handle. Examples of the hydroxy compound having an oxyethylene content of 20% by weight or more that can be used in the present invention include monohydric or higher alcohols, hydroxyl-containing amine compounds, polyvalent amino compounds, organic carboxylic acids, alkylphenols, and the like. There are polyethers obtained by addition polymerization of an alkylene oxide such as an oxide. More specific examples include water, methanol, ethanol, propanol, ethylene glycol, propylene glycol, diethylene glycol, stearyl alcohol, oleyl alcohol, cetyl alcohol, allyl alcohol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, monoethanolamine, diethanolamine Examples include those obtained by addition-polymerizing an alkylene oxide such as ethylene oxide to triethanolamine, ethylenediamine, tolylenediamine, oleic acid, stearyl acid, alkylphenol, or the like. In addition, low molecular weight hydroxy compounds, for example, low molecular weight polyols such as glycerin, trimethylolpropane, diethylene glycol, and polypropylene glycol can be used. In this case, the oxyethylene content is mixed and mixed so that the oxyethylene content is 20% by weight or more on average. Is good. If the oxyethylene content is less than 20% by weight of the hydroxy compound, it is not possible to obtain a completely open cell foam and it is difficult to produce a hydrophilic polyisocyanurate foam. In order to obtain a particularly good hydrophilic open-cell polyisocyanurate foam, the oxyethylene content in the polyhydroxy compound should be 50 or less.
It is preferable that the content be not less than% by weight. The polyester polyol used in the present invention has an average number of functional groups of 1.0 to 3.0.
5, a polyester polyol and a caprolactone obtained by reacting a polycarboxylic acid such as adipic acid with a polycarboxylic acid such as adipic acid with a polyfunctional hydroxyl group-containing compound such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, and trimethylolpropane to form a ring-opening polymer. The obtained polyester and the like are preferable, and the polycarboxylic acid is preferably an aliphatic carboxylic acid.

As the isocyanurate catalyst that can be used in the present invention, any generally known isocyanurate catalyst can be used. For example, quaternary ammonium salts, organic acid alkali metal salts, strongly basic metal salts, alcoholates and the like. Specific compounds include potassium acetate, sodium acetate, potassium octylate, sodium octylate, potassium hydroxide, NN'N "- Tris (3-dimethylaminopropyl) hexahydro-S-triazine,
And potassium alcoholate. If necessary, a polyurethane-forming catalyst such as a tertiary amine or an organic metal catalyst can be used together.

In the present invention, the preferred isocyanate index is 110 or more. As the polyoxyalkylene derivative having no active hydrogen that can be used in the present invention, a polyoxyalkylene derivative having a polyoxyalkylene chain and having a structure capped with a compound having no active hydrogen is preferable, for example, oleyl alcohol, Monofunctional alcohols such as methanol, bifunctional glycols such as polyethylene glycol, polypropylene glycol and polyethylene polypropylene glycol, and polyfunctional hydroxyl group-containing compounds such as glycerin and trimethylolpropane, and ethylene oxide, propylene oxide, or a polyfunctional compound obtained by adding both oxides. A polyol having a structure in which the terminal of the polyol is capped with a compound having no active hydrogen is preferable. Specifically, for example, a compound having a structure capped by esterification with a fatty acid such as oleic acid, or a compound having a structure capped with an alkoxy group, an acetoxy group, or an alkyl ether group, or the above-described fatty acid ester group ,
There are compounds having a structure capped with both alkoxy groups. Further, those having a structure in which an OH group terminal obtained by addition-polymerizing an alkylene oxide to a compound such as methanol or alkylphenol is capped with an alkoxy group or a fatty acid ester group are preferable, and a fatty acid ester compound is particularly preferable. In addition, polyoxyalkylene aliphatic hydrocarbon ethers such as polyoxyalkylene dioleyl ether whose terminal is masked with oleyl chloride after adding alkylene oxide to oleyl alcohol or the like can also be used. Here, the polyoxyalkylene aliphatic hydrocarbon ether refers to an ether derived from a saturated aliphatic alcohol such as caprylic alcohol and stearyl alcohol and an ether derived from an unsaturated aliphatic alcohol represented by oleyl alcohol. The present ethers can be used in the present invention whether they are monoethers or polyethers. The polyoxyalkylene alkyl aromatic hydrocarbon ether refers to polyoxyalkylene nonyl phenyl, oleyl diether, etc. obtained by adding alkyl oxide to nonyl phenol and then etherifying it with oleyl chloride or the like. That is, the polyoxyalkylene derivative having no OH group used in the present invention is a compound having a polyoxyalkylene chain, and it is sufficient that the terminal does not have an OH group. For example, monoisocyanate, diisocyanate, monoalcohol, etc. May be capped by urethane bonding. The polyoxyalkylene derivative of the present invention may be ionic or non-ionic. The higher the content ratio of polyoxyethylene in the oxyalkylene chain of the polyoxyalkylene derivative having no active hydrogen used in the present invention described above, the higher the proportion of polyoxyethylene, the more it depends on the type of polyol and the type of silicone-based foam stabilizer. In addition, the open cell effect is large, and at the same time, the water absorption and water retention tend to increase. In particular, the proportion of the oxyethylene chain content in the polyoxyalkylene chain is preferably at least 20% by weight, more preferably at least 50% by weight of the total molecular weight. The length of the polyoxyalkylene chain and the content of the oxyethylene chain may be appropriately selected depending on the type of the polyether used, the type of the silicone-based foam stabilizer, the type of the isocyanate, and the like. Examples of particularly preferred compounds used in the present invention include polyethylene glycol stearic acid diester, polyethylene glycol lauric acid diester, polyethylene glycol oleic acid diester, methyl polyethylene glycol stearic acid ester, dimethyl polyethylene glycol, polyethylene polypropylene glycol stearic acid diester, and dimethyl polyethylene. Polypropylene glycol, α-methoxypolyoxyethylene β-oleate, polyoxyethylene dioleyl ether, polyoxyethylene dilauryl ether, polyoxyethylene dinonyl phenyl ether, polyoxyethylene / diethylhexyl ether / phosphate, and the like. Glycerin,
Polyesters of trimethylolpropane, pentaerythritol and a polyol obtained by adding ethylene oxide or propylene oxide to lauric acid, oleic acid, stearic acid, and the like are also preferable.Especially, in the case of coaddition polymerization of ethylene oxide and propylene oxide, alkylene oxide is used. The content of ethylene oxide is particularly preferably 70% by weight or more.

When the polyoxyalkylene derivative having no active hydrogen of the present invention is used industrially, a pure product cannot be used, and a small amount of a compound having an OH group and free fatty acids are mixed as impurities. It can be used if not in large quantities. Although an ester having an OH group has a small effect of lowering the performance, fatty acids such as oleic acid and stearic acid themselves greatly increase the hydrophobicity and have a particularly large closed cell action, which is not preferable. Preferably, the acid value is 20 or less, more preferably 10 or less. The polyoxyalkylene derivative having no OH group used in the present invention is used in a proportion of 10 to 200 parts by weight per 100 parts by weight of the polyol, more preferably 30 to 100 parts by weight of the polyol.
It is preferably used in an amount of from 150 to 150 parts by weight. When the amount is less than 10 parts by weight, there is almost no effect. In particular, when the amount is 30 parts by weight, water drops on the foam can be absorbed immediately or in a few seconds. If the amount is more than 200 parts by weight, the strength of the foam is reduced and the practicability is poor.

The chemical structure of a representative polyoxyalkylene derivative having no active hydrogen is as follows. The silicone-based foam stabilizer used in the present invention is a polysiloxane-polyoxyalkylene copolymer.To produce a hydrophilic polyisocyanurate foam, the polyoxyalkylene terminal OH group has another OH group. It is necessary to form a structure capped with compounds that do not have. Preferable specific examples are a structure in which one or four alkoxy groups represented by a methoxy group or an ethoxy group, or an aliphatic acyloxy group represented by an acetoxy group are used alone or in combination, and the oxyethylene chain is It is preferable to contain 30% by weight or more of all oxyalkylene chains. Examples of typical chemical structures of the present polysiloxane-polyoxyalkylene copolymer are as follows. (Wherein R is CH ₃ , C ₂ H ₅ , CH ₃ CO, m is an integer of 8 or more, n is an integer of 1 or more, a is an integer of 4 or more, and b is an integer of 1 or more) (Wherein R is CH ₃ , C ₂ H ₆ , CH ₃ CO, m is an integer of 8 or more, a is an integer of 4 or more, and b is an integer of 1 or more)

As the proportion of the oxyethylene content in the total polyoxyalkylene of the polysiloxane-polyoxyalkylene copolymer of the present invention increases, the foam can be made into open cells and at the same time improve water absorption and water retention. Can be done. The preferred oxyethylene content is from 50% by weight to 90% by weight, particularly preferably from 70% by weight to 90% by weight, based on polyoxyalkylene. When the oxyethylene ratio is 90% by weight or more, the present polysiloxane-polyoxyalkylene copolymer becomes a solid, which is not only difficult to handle but also tends to decrease the water absorption rate. The oxyethylene ratio is 50
When the content is less than 100% by weight, it is difficult to form continuous cells reaching 100%, and the water absorption and water retention are reduced, and at the same time, the bubble size is increased and the bubble stability tends to be reduced. When the polyoxyalkylene terminal of the polysiloxane-polyalkylene copolymer is an OH group, the water absorption rate is extremely reduced. If it is necessary to introduce a polyoxyalkylene terminal OH group, it must be 25% or less of the total number of groups including other alkoxy groups, acetoxy groups, or aliphatic acyloxy groups. As the number of OH groups increases, the hydrophobicity increases. It is also conceivable to mix and use a polysiloxane-polyalkylene copolymer having an OH group with the silicon-based surfactant of the present invention, but the hydrophobicity is similarly increased. It is within the scope of the present invention to use the silicone surfactant having the present OH group within a range that does not impair the properties of the present foam. Generally, it is preferable to use about 0.5 to 10.0 parts by weight of the present silicone-based foam stabilizer with respect to 100 parts by weight of polyether.

As other ionic surfactants used as required in the present invention, anionic, cationic and amphoteric surfactants can be used, but anionic surfactants are preferred. For example, dodecylbenzene sulfone Sodium dialkyl sulfosuccinate, sodium alkyl diphenyl ether disulfonate, and the like. The present ionic surfactant is preferably used in combination with a polyoxyalkylene derivative having no active hydrogen as an open-celling aid and a foam-stabilizing aid, and also as a water-retention aid. .

In the first aspect of the present invention, the meaning of "optionally other ionic surfactants" refers to the use of ionic surfactants other than polyoxyalkylene derivatives having no active hydrogen and the use of ionic surfactants. No surfactant is used, both of which are within the scope of claim 1. The ionic surfactant is generally present in an amount of from 0 to 1 based on the total reaction mixture.
It is preferred to use 0% by weight.

The water-absorbing resin used in the present invention may be a general-purpose water-absorbing resin, and can be used both ionic and non-ionic. Specifically, as the ionic water-absorbing resin, a cross-linked polyacrylate, isobutylene /
There are maleic acid salt type, starch / polyacrylate type and the like, and non-ionic absorbing resins include polyether urethane type and high molecular weight polyethylene oxide. These water-absorbing resins are used in an amount of 1 per 100 parts by weight of the hydroxy compound.
It is preferably used in an amount of about 40 parts by weight, particularly preferably 3 to 20 parts by weight. If the addition amount is small, the water retention capacity is low, and if the addition amount is large, the viscosity increases when added and mixed with the hydroxy compound as a raw material, and stable discharge measurement cannot be performed, and a good foam cannot be obtained, which is not preferable.

The hydrophilic open-cell polyisocyanurate foam of the present invention needs to have a density of 8 to 70 kg / m ³ . If the density is 8 kg / m ³ or less, there is a lot of space in the foam, and the water absorption capacity of the foam rib by the capillary decreases, and the water retention in the foam decreases, which is not preferable. When the density is 70 kg / m ³ or more, the water absorption capacity is improved, but the water absorption is low, which is not preferable. The hydrophilic open-cell isocyanurate foam of the present invention preferably has an open-cell ratio of 98% or more. The open cell ratio is ASTM D2856-70.
Measured by procedure B. Open cell rate 9
If it is less than 8%, it takes several hours to absorb water because 2% or more closed cells give buoyancy and float the foam on the water surface,
Even if the upper surface is wetted with water, water does not enter into the open cells, and thus the water absorption is small. When the open cell ratio is low, a small amount of ink is immediately absorbed in the case of a waste ink absorbing material of an ink jet printer or the like, but a large amount of waste ink is not easily absorbed and is not preferable. In particular, when the open cell ratio reaches 100%, it is particularly preferable that the foam floats on the water surface because it sinks below the water surface in several seconds to several tens of seconds. Foams with an open cell ratio of up to 100% have a low thermal conductivity due to a complete vacuum in the case of vacuum panel insulation, and have high efficiency especially for anti-condensation materials, humidity absorption / release adjustment materials and waste ink absorbers. preferable.

The foaming agent used in the present invention can sufficiently achieve its purpose even with water alone. However, if necessary, pentane, hexane, dichloromethane, 1,1-dichloro-1 can be used.
It is also possible to use low-boiling liquids such as fluoroethane. In the present invention, well-known additives and fillers generally used can be added. For example, inorganic fillers such as calcium carbonate and barium sulfate, pigments or antioxidants, ultraviolet inhibitors, nonionic surfactants and the like.

[0017]

The object of the present invention is to provide hydrophilic open-celled polyisocyanurate foams having a capacity of up to 100% which have the capacity to absorb water as well as to retain water immediately. It is another object of the present invention to provide a hydrophilic open-celled polyisocyanurate foam having a capacity of 100% capable of absorbing and releasing moisture in the air. Another object of the present invention is to provide a hydrophilic open-cell polyisocyanurate foam having a compression crushing strength of 100% which shows a substantially constant value at 10 to 60%. In the present invention, it is considered that it is particularly difficult to make the cells open and hydrophilic, and the present invention has been completed by achieving open cells and hydrophilicity based on polyisocyanurate foam which has been avoided in the industry.

That is, the present invention provides an aromatic isocyanate,
A hydroxy compound comprising a polyether and / or polyester having an oxyethylene content of 20% by weight or more,
Isocyanurate-based catalyst, polysiloxane-poly having a structure in which the oxyalkylene terminal is capped with an alkoxy group and / or a lower aliphatic acyloxy group and the oxyethylene chain content in the polyoxyalkylene chain is 30% by weight or more. 100% by using a silicone-based foam stabilizer as an alkylene copolymer, a polyoxyalkylene derivative as a special additive having no active hydrogen, a foaming agent, and other ionic surfactants as required. A hydrophilic open cell polyisocyanurate foam having an open cell ratio was completed. The present invention particularly relates to a polyhydroxy compound comprising a polyether and / or polyester having an oxyethylene content of 20% by weight or more, and a special polysiloxane-polyoxyalkylene copolymer having a graft oxyalkylene terminal capped with an alkoxy group or the like. In addition, open cells and hydrophilicity reaching 100% were achieved by the synergistic effect of the polyoxyalkylene derivative having no active hydrogen. In particular, polyoxyalkylene derivatives having no active hydrogen make the foaming reaction and gelling reaction mild, work to obtain a uniform and complete open-cell foam, and make the hydrophobic polyisocyanurate foam completely hydrophilic. Was also achieved. In addition, it is surprising that a completely open-celled polyisocyanurate foam reaching 100% was produced, and the hydrophilicity was able to be achieved while being an isocyanurate foam. In the present invention,
When a silicon-based surfactant such as an oxyalkylene-terminated OH group that is a silicon-based surfactant that is a polysiloxane-polyoxyalkylene copolymer specified by the present invention is used, hydrophilic open-celled polyisocyanurate is used. No system is available. In addition, even if the silicone-based surfactant specified in the present invention is used, a hydrophilic open-celled polyisocyanurate foam cannot be obtained if the polyoxyalkylene derivative which is the special additive specified in the present invention is deleted. Also, the hydrophilic open-cell polyisocyanurate foam can be obtained by using the silicon-based surfactant specified in the present invention, not using the special additive of the present invention, and using a large amount of another ionic surfactant. I can't. Similarly, a silicon-based surfactant having an OH group or the like that uses the silicon-based surfactant specified in the present invention is used, and a large amount of other ionic or non-ionic surfactants are used regardless of the use of the special additive of the present invention. The use of ionic surfactants does not provide hydrophilic open-cell polyisocyanurate foams. Similarly, the hydroxy compound does not satisfy the conditions of the present invention, and a hydrophilic open-celled polyisocyanurate foam cannot be obtained even when an ionic surfactant is used. From this, it can be said that the hydrophilic open-celled polyisocyanurate foam of the present invention having the property of absorbing water instantaneously has a synergistic effect of a specific hydroxy compound, a specific silicone-based foam stabilizer and a specific special additive. . A hydroxy compound comprising a polyether and / or a polyester having an oxyethylene chain of 20% by weight or more, and a polyoxyalkylene derivative having no active hydrogen when being made into continuous cells by the silicone-based foam stabilizer specified in the present invention. Unless the content is more than 10 parts by weight per 100 parts by weight of the hydroxy compound, 100% open cells cannot be obtained and a fine cell foam cannot be produced stably. In general, polyurethane foams are basically made of closed-cell or open-cell foams by the action of a silicone-based surfactant, but the method of producing this foam does not follow the conventional mechanism and is a subversion of common sense. That is, when the polyoxyalkylene derivative having no active hydrogen is deleted from the foam system in the foam formulation of the present invention,
The foam foams while defoaming and becomes a coarse cell, and does not become a good foam. By adding a polyoxyalkylene derivative having no active hydrogen to the foam having low cell stability, a fine and good cell foam can be obtained.
That is, the polyoxyalkylene derivative having no active hydrogen not only makes the obtained foam hydrophilic, but also acts as an open-cell foaming agent and a foam stabilizer.
These actions are considered to be a synergistic effect of a specific polyol, a specific silicone foam stabilizer, and a polyoxyalkylene derivative having no active hydrogen.

In particular, when the polyoxyalkylene derivative of the present invention and the silicon-based surfactant of the present invention are integrated, they instantly absorb water. This is surprising compared to the fact that ordinary water-absorbent resins have the property of absorbing a large amount of water, but do not have the property of absorbing water instantaneously. The aforementioned two components and a crosslinked polymer derived from a specific hydroxy compound are integrated, and a special silicon-based foam stabilizer and the polyoxyalkylene derivative of the present invention bleed on the rib surface of the completed foam, and are likely to be hydrophilic. It is considered to have given the sex. It is presumed that these special silicone-based foam stabilizers have hydrophilic alkoxy groups or the like aligned in the ribs on the foam surface toward the surface. In the present invention, an ionic surfactant may be used. However, the ionic surfactant is used not for increasing the water absorption rate but for increasing the water absorbing power. In the hydrophilic open-cell polyisocyanurate foam of the present invention, the pores of the cells mean the pores of the capillary. That is, the foam of the present invention is 10 mm × 10 mm
When standing in a water of 10 mm height as a rod shape of 100 mm, water rises from the lower surface by a capillary tube. Usually, it rises by about 25 mm to 30 mm, but when used together with an ionic surfactant, it rises to a height of 30 mm to 40 mm. That is, the water retention force is increased by the water absorbing effect of the capillary. In order for the anti-condensation material, humidity absorption / release control material, waste ink absorber for printers, etc., to be used in the present invention more efficiently, a hydrophilic open-celled polyisocyanurate foam that completely reaches 100% is required. . In particular, waste ink absorbers for inkjet printers absorb ink very quickly,
Moreover, complete retention is required. As for heat insulation of refrigerators, vacuum panel heat insulation has recently been introduced, and open-celled rigid foam is being used as a shape-retaining material. However, a completely open-cell foam is not desired because it does not sufficiently exhibit the excellent heat insulating effect of vacuum unless it is 100% open cells. Furthermore, hydrophilic polyisocyanurate foams reaching 100% are also preferred in the field of impact absorbing foams such as impact absorbing foams to be inserted into automobile bodies and the like.

According to the fourth aspect of the present invention, the water-absorbing resin is used in combination, whereby the water is immediately absorbed and the water is strongly retained. That is, when a water drop on the foam is dropped, water is instantly absorbed and a property that water is not released with a small pressure is added. Generally, a water-absorbing resin has a property of absorbing a large amount of water over time, but does not absorb water instantaneously.
Further, when added to a foam, the surface of the water-absorbent resin powder is covered with a polymer, so that the water absorption rate further decreases. However, in the present invention, the foam of the present invention except for the water-absorbent resin powder absorbs water instantaneously, and has a two-stage absorption and retention that the water-absorbent resin does not strongly receive the absorbed water. it is conceivable that.

[0021]

The present invention will be specifically described below with reference to examples and comparative examples. The raw materials used in the examples and comparative examples are as follows. polyol-1: a polyether polyol having a molecular weight of 3400 obtained by addition polymerization of glycerin with ethylene oxide and propylene oxide at a weight ratio of 78/22. polyol-2: a polyol having a molecular weight of 3000 obtained by addition polymerization of glycerin and propylene oxide. 3: Polyester polyol synthesized from diethylene glycol, glycerin and adipic acid and having an average number of functional groups of about 3 and a molecular weight of 3000. Polyol-4: Stearyl alcohol is mixed with ethylene oxide and propylene oxide in a weight ratio of 75/2.
Polycat 41 having a molecular weight of 1350, which was addition-polymerized at a ratio of 5: manufactured by Air Products Japan,
NN'N "-tris (3-dimethylaminopropyl) hexahydro-S-triazine Silicon-based surfactant-1: Polydimethylsiloxane copolymer having the structure of Formula 8 Ethylene oxide / propylene oxide weight ratio 80/20 , MW = 120
0, m / n = 40/1, R = CH ₃ silicon-based surfactant-2: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8;
The weight ratio of ethylene oxide / propylene oxide is 78/22, m / n = 40/2, and R = CH ₃ silicon-based surfactant-3: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8 ,
Ethylene oxide / propylene oxide is 80/20 by weight, MW = 1600, m / n = 30/3, R =
CH ₃ silicon-based surfactant-4: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8;
Ethylene oxide / propylene oxide is 60/40 by weight, MW = 1500, m / n = 40/1, R =
CH ₃ silicon-based surfactant-5: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8;
Ethylene oxide / propylene oxide is 80/20 by weight, MW = 1150, m / n = 30/3, R =
H silicon-based surfactant-6: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8;
Ethylene oxide / propylene oxide is 75/25 by weight, MW = 1600, m / n = 30/1, R =
CH ₃ CO silicon-based surfactant-7: a polydimethylsiloxane-polyoxyalkylene copolymer having the structure of Formula 8;
Ethylene oxide / propylene oxide is 60/40 by weight, MW = 1400, m / n = 30/1, R =
CH ₃ additive-1: polyoxyethylene dioleate, polyoxyethylene glycol has a molecular weight of 600 Additive-2: triglyceride of a polyether polyol having a molecular weight of 1200 obtained by addition-polymerizing ethylene oxide to glycerin and methyl oleate. Ester Additive-3: Monoester of oleic acid with monool having a molecular weight of 330 obtained by addition polymerization of ethylene oxide to methanol Additive-4: Polyoxyethylene dioleyl ether,
Polyoxyethylene molecular weight 560 Additive -5: Triester of polyether polyol having a molecular weight of 1000 obtained by addition polymerization of glycerin with ethylene oxide and methyl oleate Additive -6: Ethylene oxide at a weight ratio of 70/30
Molecular weight 3 randomly polymerized with propylene oxide
Polyoxyethylene derivative in which n-octanol is masked at both ends of polyether diol with tolylene diisocyanate (TDI-65). Sunfresh ST500MPS: manufactured by Sanyo Chemical Industries, Ltd.
Electrolyte-based water-absorbing resin Newcol 271S: manufactured by Nippon Emulsifier Co., Ltd., aqueous solution of sodium alkyldiphenyl ether sulfonate Sanmorin OT-70N: manufactured by Sanyo Kasei Kogyo Co., Ltd., aqueous solution of sodium dioctyl sulfosuccinate Irganox 1010: manufactured by Ciba Specialty Chemicals, antioxidant Agent papi-135: Dow Polyurethane Japan Co., Ltd., crude polymethylene polyphenylene isocyanate

The method for measuring the physical properties of the polyisocyanurate foams of the examples and comparative examples is as follows. 10%, 40% compression hardness (Kgf / cm ² ): length 30 m
A sample of mx 30 mm wide x 20 mm thick is compressed at a rate of 5 mm / min, and the hardness at the time of 10% and 40% compression of the thickness. This hardness is a value specified by ASTM1621-73, and the zero point of the compression ratio is shown in FIG. Other measurement conditions were measured according to the above ASTM1621-73. Open cell ratio (%): ASTM D2856-70 pro
measured with CedureB. Water Time (sec): Needle standard 22G × ^{1 1/4} _"(Nipro Co., Ltd.) dropwise pure drop from the syringe, the time until the drop is completely absorbed in the foam immersion time (in seconds):. Vertical 50mm × width 50mm × height 40m
m floats on the surface of the water until it completely sinks,
However, the test time is up to 15 minutes. Water absorption (vol./vol.) (%): The foam used for measuring the immersion time is pulled up, the weight is measured, and the water absorption is calculated. Convert 1 g of water to 1 cm ³ , convert the water absorption volume, divide by the foam volume and express in%. Water absorption retention (%): The foam used for measuring the water immersion time is pulled up and the weight (A) is measured. This foam is placed on a wire mesh with a tilt angle of 30 °, and the weight after 1.5 hours (B)
Is measured and calculated by the following equation.

In Examples 1 to 8, polyisocyanurate foams were produced by the hand stirring method according to the formulations shown in Tables 1 and 3. Tables 2 and 4 show the physical properties. All foams from Examples 1 to 8 were completely open-cell foams, and were hydrophilic polyisocyanurate foams having good water absorption and water retention. The foam of Example 6 was subjected to pressure after the water retention test, but unlike the other foams, did not readily release water.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

Table 5 shows the formulations of Comparative Examples 1 to 4, and Table 6 shows the physical properties of the foams. In Comparative Example 1, when a silicon-based surfactant having an OH group at a polyoxyalkylene terminal was used, additive-1 which was a polyoxyalkylene derivative having no active hydrogen and Newcol 271S which was an anionic surfactant were used. The foam does not absorb water when used. In Comparative Example 2, when the polyoxyalkylene derivative having no active hydrogen is not used even when the anionic surfactant 271S and the specific silicon are used, the foam can be formed but does not absorb water. In Comparative Example 3, when the silicone-based foam stabilizer of the present invention was used but the anionic surfactant 271S and the polyoxyalkylene derivative having no active hydrogen were not used, the foam was foamed by defoaming during foaming. Can not. Comparative Example 4 is an example using a polyoxypropylene polyol having no polyoxyethylene chain, but absorbs water but has a very long water absorption time.

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

According to the present invention, the hydrophobic closed-cell polyisocyanurate foam is converted into a hydrophilic open-cell polyisocyanurate foam, and a completely open-cell foam of up to 100% is made possible. Since this foam has the property of absorbing and retaining water instantly, it is useful as a dew-prevention material inside a house, a humidity absorption / release adjusting material, and a waste ink absorbing material for inkjet printers. Since this foam is a completely open-cell foam, it is also useful as a vacuum panel heat insulator for refrigerators and the like. The foam has a constant compressive crushing strength of 10% to 60% and is useful as an impact absorbing material.

[Brief description of the drawings]

FIG. 1 specifies a zero point in a hardness measurement method according to ASTM 1621-73.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08G 101: 00)

Claims (12)

[Claims] 1. A polyisocyanurate foam comprising a polyisocyanate compound, a hydroxy compound, water and / or another foaming agent, a catalyst, a silicone-based foam stabilizer, a special additive, and if necessary, another ionic surfactant. 1) a polyisocyanate is an aromatic polyisocyanate compound, and 2) a hydroxy compound comprising a polyether and / or polyester having an average number of functional groups of 1.0 or more and an oxyethylene content of 20% by weight or more. And 3) the catalyst uses at least an isocyanurate-based catalyst, and 4) the silicon-based foam stabilizer is a polysiloxane-polyoxyalkylene copolymer, and the polyoxyalkylene polyether end has another active hydrogen. It has a structure capped with a compound that does not have Is a silicon-based foam stabilizer containing 30% by weight or more of oxyethylene, 5) a polyoxyalkylene derivative in which the special additive does not have active hydrogen, and 6) 10% by weight of the special additive per 100 parts by weight of the hydroxy compound. Parts or more, and the foam density is 8 to 1
A method for producing a hydrophilic open-cell polyisocyanurate foam having a weight of 00 kg / m ³ . 2. The silicone-based foam stabilizer is a polysiloxane-polyoxyalkylene copolymer, and the polyoxyalkylene polyether end has a C _{1 to} C ₄ alkoxy group or an acyloxy group. A method for producing a hydrophilic open-cell polyisocyanurate foam according to the above. 3. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 1, wherein an anionic surfactant is used in combination. 4. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 1, wherein a water-absorbing resin is used in combination. 5. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 1, wherein the special additive is a polyoxyalkylene alcohol fatty acid ester. 6. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 5, wherein the fatty acid is mainly lauric acid, stearic acid, oleic acid, linolenic acid, or linoleic acid. 7. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 1, wherein the special additive is a polyoxyalkylene aliphatic hydrocarbon ether and / or a polyoxyalkylene alkyl aromatic hydrocarbon ether. 8. The method for producing a hydrophilic open-cell polyisocyanurate foam according to claim 1, wherein the oxyethylene content of the hydroxy compound is 50% by weight or more. 9. The method according to claim 1, wherein the amount of the special additive is at least 30 parts by weight per 100 parts by weight of the hydroxy compound.
Or a method for producing a hydrophilic open-celled polyisocyanurate foam according to any one of items 7 to 7. 10. A hydrophilic open-cell polyisocyanurate foam, wherein the foam produced by the method according to claim 1 is used as an impact-absorbing foam. 11. A hydrophilic open-cell polyisocyanurate foam, wherein the foam produced by the method according to claim 1 is used as a vacuum panel insulator for refrigerators. 12. A hydrophilic open-cell polyisocyanurate foam, wherein the foam produced by the method according to claim 1 is used as a waste ink absorbent.