JPH11228662A - Polyisocyanate for rigid spray foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyisocyanate for hard spray foam having excellent workability, dimensional stability, adhesiveness and the like, which is used for in-situ foaming of a hard spray foam using water as a blowing agent. SOLUTION: The content of ethylene oxide is 70% by weight.
Above, the number average molecular weight of 300 to 2,000 polyether monool or polyether polyol 0.0
The problem is solved by using an MDI-based isocyanate group-terminated prepolymer containing 1 to 20% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyisocyanate for a hard spray foam used for thermal insulation, spraying work and the like. More specifically, the present invention relates to a polyisocyanate for a hard spray foam capable of obtaining a hard spray foam excellent in workability, adhesion to an adherend, dimensional stability, and the like.

[0002]

2. Description of the Related Art Conventionally, polyurethane-based in-situ foamed rigid spray foams are usually obtained by spray foaming a polyol liquid and a polyisocyanate liquid in the presence of a foaming agent, a catalyst and a foam stabilizer. As this blowing agent, trichlorofluoromethane (hereinafter, CFC-
11) has been widely used. However, in recent years, ozone layer destruction has been highlighted as an environmental problem. Reduction and elimination of chlorofluorocarbon (including CFC-11), which is one of the substances causing the depletion of the ozone layer, have begun to be implemented. Therefore, dichlorotrifluoroethane (hereinafter referred to as HCFC-
123), dichlorofluoroethane (hereinafter, abbreviated as
HCFC-141b) is considered as an alternative to CFC-11. However, this alternative CFC is expected to be reduced and eliminated in the near future. For these reasons, water has begun to be studied as a blowing agent.

[0003] However, using water as a blowing agent raises several problems. For example: (1) The obtained foam has poor dimensional stability. (2) Adhesion with an adherend is deteriorated. (3) Poor workability in in-situ foaming at low temperature. And so on.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hard spray foam having excellent workability, dimensional stability, adhesiveness and the like, which is used for in-situ foaming of a hard spray foam using water as a foaming agent. The purpose is to provide a polyisocyanate for use.

[0005]

That is, the present invention provides the following (A) a polyisocyanate and a (B) modifier, wherein (A) :( B) = 80-99.99: 20-0.0
A polyisocyanate for a hard spray foam, which is obtained by reacting at a ratio of 1 (weight ratio). (A) Polyisocyanate: a polyisocyanate containing the following (A) and (B). (A) diphenylmethane diisocyanate. (B) Polyphenylene polymethylene polyisocyanate. However, (A): (B) = 20-70: 80-30 (weight ratio) (B) Modifier: Ethylene oxide content is 70% by weight
As described above, a polyether monool or a polyether polyol having a number average molecular weight of 300 to 2,000.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each raw material used in the present invention will be described. The polyisocyanate (A) used in the present invention includes (a) diphenylmethane diisocyanate (hereinafter abbreviated as MDI) and (b) polyphenylenepolymethylene polyisocyanate (hereinafter, polymeric MD)
Abbreviated as I). (B) MDI
Is a compound having two benzene rings and two isocyanate groups in one molecule, and is called a binuclear body. Further, (b) polymeric MDI has three or more benzene rings and isocyanate groups in one molecule, and is called a polynuclear.

(A) The isomers constituting MDI are 2,2
2'-diphenylmethane diisocyanate (hereinafter referred to as 2,
2'-MDI), 2,4'-diphenylmethane diisocyanate (hereinafter abbreviated as 2,4'-MDI), 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as 4,4'-MDI) There are three types. The isomer composition ratio of MDI is not particularly limited.
It is preferable that the 4'-MDI content be 70% by weight or more, since the strength of the obtained foam is improved.

In the present invention, the ratio of (A) MDI to (B) polymeric MDI is (A) :( B) = 20 to 7
0: 80-30 (weight ratio), preferably 25-65: 7
5 to 35 (weight ratio). When (a) is less than the lower limit, the workability of the hard spray foam is likely to be reduced. On the other hand, when (a) exceeds the upper limit, the strength of the hard spray foam is reduced and the hard spray foam tends to become brittle.

In addition, an isocyanate other than MDI and polymeric MDI may be used in combination in the present invention, if necessary. For example, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, xylene-1,4
-Diisocyanate, xylene-1,3-diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-
4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-
1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,
4'-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 3-methyl-
1,5-pentane diisocyanate, aliphatic diisocyanate such as lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethyl xylene diisocyanate, these polymeric materials, these urethane modified products, Urea-modified, allophanate-modified, biuret-modified, carbodiimide-modified, uretonimine-modified, uretdione-modified, isocyanurate-modified,
Further, a mixture of two or more of these may be mentioned.

As the modifier (B) used in the present invention, a compound having an active hydrogen group such as the following compounds is used as an initiator, and ethylene oxide (hereinafter referred to as EO) is used.
Propylene oxide (hereinafter abbreviated as PO), alkylene oxides such as butylene oxide and amylene oxide, alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, tetrahydrofuran and the like. EO alone or EO
And a mixture of alkylene oxides other than EO, alkyl glycidyl ethers, aryl glycidyl ethers, cyclic ethers and the like by addition polymerization by a known method. Examples of initiators Low molecular monols: methanol, ethanol, normal propanol, isopropanol, normal butanol, sec-butanol, ter-butanol, phenol, cyclohexanol, etc. Low molecular polyols: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-
Butanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol , Neopentyl glycol, 3-methyl-
1,5-pentanediol, cyclohexane-1,4-
Diol, cyclohexane-1,4-dimethanol, bisphenol A, hydrogenated bisphenol A, glycerin, trimethylolpropane, pentaerythritol,
Sorbitol, also low-molecular-weight polyamines such as sucrose, glucose, fructose: ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine,
Diphenylmethanediamine, xylylenediamine, etc.

The modifier (B) used in the present invention is EO
A polyether monool or polyether polyol having a content of 70% by weight or more, preferably 80% by weight or more, and a number average molecular weight of 300 to 2,000, preferably 500 to 1,500. Preferred in the present invention are polyether monols using low molecular weight monols having 1 to 4 carbon atoms as initiators.

In addition, if necessary, the compound may be modified with an active hydrogen group-containing compound other than the modifier (B). (B) Examples of the active hydrogen group-containing compound other than the modifier include the following. -Low molecular monols: methanol, ethanol, normal propanol, isopropanol, normal butanol, sec-butanol, ter-butanol, phenol, cyclohexanol, etc.-Low molecular polyols: ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8- Octanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-
1,5-pentanediol, cyclohexane-1,4-
Diol, cyclohexane-1,4-dimethanol, bisphenol A, hydrogenated bisphenol A, glycerin, trimethylolpropane, pentaerythritol,
Sorbitol, sucrose, glucose, fructose, etc.-Low molecular polyamines: ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc.-Low molecular amino alcohols: monoethanolamine,
Monopropanolamine, diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, N-methyldiethanolamine, N, N-
Dimethylethanolamine, etc.-Polyester polyols and polyester amide polyols: one or more of the above low molecular polyols, low molecular polyamines, low molecular amino alcohols, and succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid One kind of polycarboxylic acid such as acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, acid ester, acid anhydride, acid halide, etc. What is obtained from the above condensation reaction. -Lactone-based polyester polyols or polyester monools: Cyclic ring such as ε-caprolactone using at least one of the above-mentioned low molecular weight monols, low molecular weight polyols, low molecular weight polyamines and low molecular weight amino alcohols as an initiator. Those obtained by ring-opening polymerization of ester (lactone) monomers. Polycarbonate polyols: those obtained by a condensation reaction of the above low-molecular polyols with diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate and the like. -Polyether polyol or polyether monool In the present invention, (B) a polyether polyol or polyether monool other than the polyether polyol or polyether monool used as a modifier.

By reacting the above-mentioned raw materials, the polyisocyanate for a hard spray foam of the present invention can be obtained. At this time, the charged weight ratio of the (A) polyisocyanate and the (B) modifier is (A) :( B) = 80 to 99.9.
9: 20-0.01, preferably 85-99.95: 1
5 to 0.05. When (B) is less than the lower limit, there is no effect in improving the foaming activity when water is used as the foaming agent. When (B) exceeds the upper limit, the strength of the obtained foam decreases.

As the method for producing the polyisocyanate for a rigid spray foam of the present invention, a known method is used. For example, a method in which all the isocyanate components and all the modifiers are reacted at once, a method in which a part of the isocyanate is reacted with the modifier, and then the remaining isocyanate is blended are exemplified. The reaction temperature in the reaction between the isocyanate and the modifier (urethane-forming reaction) is 30 to 120 ° C., preferably 4 ° C.
0-100 ° C. Further, at the time of the urethanization reaction, if necessary, an urethanization catalyst such as an organic metal compound such as dibutyltin dilaurate or dioctyltin dilaurate, or an organic amine such as triethylenediamine or triethylamine or a salt thereof may be used.

The polyisocyanate for a rigid spray foam of the present invention thus obtained has an isocyanate content of 25 to 33% by weight, preferably 26 to 32% by weight.
It is.

The polyisocyanate for a hard spray foam of the present invention may contain, if necessary, an emulsifier, a surfactant, an antioxidant, an ultraviolet absorber, a filler, a flame retardant, a plasticizer, a pigment / dye, an antibacterial agent, and an antimicrobial agent. Known various additives and auxiliaries such as a fungicide can be added.

A rigid spray foam is obtained by mixing and spraying the thus obtained polyisocyanate for a rigid spray foam with a polyol premix blended in advance with the polyol premix.

The blending of the polyol premix at this time is not particularly limited, but generally a blend of a polyether polyol, a polyester polyol, a polymer polyol, a foaming agent, a foam stabilizer, a catalyst and the like is used as appropriate.

[0019]

The polyisocyanate of the present invention has been found to be particularly excellent in the reactivity with water as compared with the conventional polyisocyanate for hard spray foam. For this reason, the polyisocyanate of the present invention is suitable for in-situ foaming using water as a foaming agent, particularly for isocyanurate foam formulation, and the obtained hard spray foam shows excellent workability, dimensional stability and adhesiveness. Was. The polyisocyanate for hard spray foam of the present invention can be applied to concrete houses, bathtubs, low-temperature tank equipment, freezing warehouses, pipe covers, spraying on plywood, various heat insulating materials, and the like.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “parts” indicates “parts by weight” and “%” indicates “% by weight”.

[Synthesis of Polyisocyanate for Hard Spray Foam] Example 1 13 parts of MDI (1) and 61 parts of P-MDI (2) were placed in a reactor equipped with a stirrer, a cooling pipe, a nitrogen introducing pipe, and a thermometer.
Parts, 24 parts of P-MDI (3), and stir 4
Warmed to 0 ° C. Next, 2 parts of the modifier (1) was charged,
The mixture was reacted at 80 ° C. for 4 hours with stirring to obtain polyisocyanate P-1 for a hard spray foam. The NCO group content of P-1 was 30.6%.

Examples 2 to 15 and Comparative Examples 1 to 3 In the same manner as in Example 1, the raw materials and the charge ratios shown in Tables 1 to 3 were used to prepare the polyisocyanates P-2 to P-2 for hard spray foam.
18 was obtained.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

Examples 1 to 15, Comparative Examples 1 to 3, Tables 1 to 3
MDI (1): 4,4'-MDI content in MDI = 100% MDI (2): 4,4'-MDI content in MDI = 50% P-MDI (1): MDI / polymeric MDI = 40/60 (weight ratio) 4,4'-MDI content in MDI = 100% Isocyanate content = 31.0% P-MDI (2): MDI / polymeric MDI = 41/59 (weight ratio) In MDI 4,4'-MDI content = 100% Isocyanate content = 31.2% P-MDI (3): MDI / polymeric MDI = 34/66 (weight ratio) 4,4'-MDI content in MDI = 100% isocyanate content = 30.7% P-MDI (4): MDI / polymeric MDI = 20/80 (weight ratio) 4,4′-MDI content in MDI = 100% isocyanate content Amount = 28.5% Modifier (1): number average molecular weight = 700 EO / PO = 100/0 (weight ratio) Initiator = methanol, average number of functional groups = 1.0 Modifier (2): number average molecular weight = 500 EO / PO = 100/0 (weight ratio) Initiator = methanol, average number of functional groups = 1.0 Modifier (3): number average molecular weight = 1,500 EO / PO = 90/10 (weight ratio) Initiator = Ethanol, average number of functional groups = 1.0 Denaturant (4): Number average molecular weight = 1,000 EO / PO = 90/10 (weight ratio) Initiator = ethylene glycol, average number of functional groups = 2.0

[Preparation of Polyol Premix] Preparation Examples 1 and 2 A polyol solution was prepared according to the formulation shown in Table 4.

[0028]

[Table 4]

In Table 2, Polyol (1): Polyethylene terephthalate-based polyester polyol Average number of functional groups = 2.0 Hydroxyl value = 250 mg KOH / g Polyol (2): Mannich-type polyester polyol Average number of functional groups = 2.0 Hydroxyl value = 450 mg KOH / g polyol (3): initiator = poly (oxypropylene) polyol of propylene glycol average number of functional groups = 2.0 hydroxyl value = 450 mgKOH / g polyol (4): initiator = poly (oxypropylene) polyol of propylene glycol average functionality Number of groups = 2.0 Hydroxyl value = 350 mgKOH / g TCPP: Tris (β-chloropropyl) phosphate Catalyst (1): Potassium octylate Catalyst (2): Lead octylate Catalyst (3): Kaolyzer No. 10. Amine-based catalyst (manufactured by Kao) Catalyst (4): Toyocat-TMF, amine-based catalyst (manufactured by Tosoh) Foam stabilizer (1): SZ-1642, silicon-based foam stabilizer (manufactured by Nippon Unicar) 2): F-338, silicone-based foam stabilizer (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Evaluation of Polyisocyanate for Hard Spray Foam] Applied Examples 1 to 16, Applied Comparative Examples 1 to 4 Comparative Example 4 was evaluated by foaming with a urethane formulation. Reactivity test Polyisocyanate solution (solution temperature: 2)
(0 ° C.) and a polyol liquid (liquid temperature: 20 ° C.), foamed by hand, and checked for reactivity. The results are shown in Tables 5 to 8. Dimensional stability, strength, adhesion measurement test Polyisocyanate liquid (liquid temperature: 2) at the ratios shown in Tables 5 to 8
0 ° C.) and a polyol liquid (liquid temperature: 20 ° C.), an aluminum paper was set inside in advance, and then the compounding liquid was poured into a mold whose temperature was adjusted to 60 ° C., and after 10 minutes, the mold was removed to obtain a foam. . The dimensional stability, strength and adhesion of this foam were measured. The results are shown in Tables 5 to 8. Sample for measuring dimensional stability Mold size (inner diameter): 60 mm x 500 mm x 500 mm Measurement conditions: 150 ° C / 2 days (No measurement was performed for Application Example 16 and Application Comparative Example 4) 70 ° C x 95% RH / 2 days- 20 ° C./2 days Sample for measuring strength and adhesion Mold size (inner diameter): 35 mm × 500 mm × 50
For the 0 mm strength, measure the core part of the sample (JIS A-9).
526) Adhesion is measured by measuring the adhesion between foam and aluminum paper

[0031]

[Table 5]

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

Applied Examples 17-18, Applied Comparative Examples 5-6 Polyisocyanate liquids at the ratios shown in Table 9 (liquid temperature: 40
° C) and a polyol liquid (liquid temperature: 40 ° C) by spraying and foaming. Table 9 shows the results. The spray foaming conditions are as follows. Substrate Slate plate Foaming machine Gasmer spray foaming machine (FF-1600 type) Primary heater temperature 45 ° C Hose heater temperature 40 ° C Adherend temperature 0 ° C Foam thickness 30mm

[0036]

[Table 9]

[Table 7]

[Table 7]

Claims (1)

[Claims] 1. A polyisocyanate (A) and a modifying agent (B) shown below, wherein (A) :( B) = 80 to 99.9.
A polyisocyanate for a rigid spray foam, which is obtained by reacting at a ratio of 9:20 to 0.01 (weight ratio). (A) Polyisocyanate: a polyisocyanate containing the following (A) and (B). (A) diphenylmethane diisocyanate. (B) Polyphenylene polymethylene polyisocyanate. However, (A): (B) = 20-70: 80-30 (weight ratio) (B) Modifier: Ethylene oxide content is 70% by weight
As described above, a polyether monool or a polyether polyol having a number average molecular weight of 300 to 2,000.