JPS61268736A - Thermal insulating and flame-retarding rigid foam - Google Patents

Abstract

PURPOSE:To obtain a foam with outstanding thermal insulation and flame- retardancy, by incorporating a blend of polyol and polyisocyanate with the ratio of isocyanate group to hydroxyl one falling in a specific range with copolymerization catalyst, foaming agent, flame-retardant and foam stabilizer followed by expansion. CONSTITUTION:The objective foam can be obtained by incorporating (A) a blend of polyol and polyisocyanate with a ratio NCO/OH falling between 0.7 and 1.5 (pref. 0.9 and 1.2) with (B) 1-15pts.wt., based on 100pts.wt. of the polyisocyanate, of an isocyanate group polymerization catalyst such as sodium phenolate, (C) 5-50pts.wt., based on 100pts.wt. of polyisocyanate, of a foaming agent such as water or pentane, (D) 60-200pts.wt., based on 100pts.wt. of the polyisocyanate, of a flame-retardant, pref. at least one kind of compound selected from aluminum hydroxide, calcium hydroxide and magnesium hydroxide, and (E) 1-10pts.wt., based on 100pts.wt. of the polyisocyanate, of a foam stabilizer, pref., silicone oil such as polymethylsiloxane, followed by polymerization and expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a heat-insulating and flame-retardant rigid foam that is widely used in the field of building materials and the like.

[Conventional technology]

Organic foams such as polyurethane foam are lightweight, inexpensive, and have very low thermal conductivity, so they are widely used as core materials for panels commonly known as "sandwich panels" or as other materials in the field of building materials. It is used.

However, organic foams usually generate a large amount of harmful black smoke when exposed to flame, and have low heat resistance.Additionally, as regulations regarding their flame retardancy are tightened year by year, they are becoming increasingly popular in the interior decoration field. Coupled with the fact that its use does not meet regulatory values, its use in fields such as building materials has been restricted.

Therefore, in the past, polyisocyanurate foam with aluminum hydroxide, calcium hydroxide, or magnesium hydroxide coexisting as a flame retardant has been proposed as a material that satisfies such regulatory values for flame retardancy. (Special Publication No. 52-35.400).

[Problem that the invention seeks to solve]

However, the problem with this conventional polyisocyanurate foam is that its cells are uneven and rough throughout, and its strength is also brittle, making it difficult to use in fields that require a certain degree of mechanical strength. was there.

[Means for solving problems]

The present invention was devised in view of this point of view, and provides a rigid foam that has excellent heat insulation and flame retardancy, as well as excellent mechanical strength.

That is, the present invention uses polyisocyanate and polyol blended so that the ratio of isocyanate groups to hydroxyl groups (NCO/OH) is within the range of 0.7 to 1.5.
The present invention provides a heat-insulating and flame-retardant rigid foam produced by coexisting an isocyanate copolymerization catalyst, a blowing agent, a flame retardant, and a foam stabilizer.

The polyisocyanate used in the present invention is a compound having at least two or more isocyanate groups, such as 2,4-tolylene diisocyanate, 2,6-
Tolylene diisocyanate, diphenylmethane-4,4
°-diisocyanate, 3-methyldiphenylmethane-
Diisocyanates such as 4,4′-diisocyanate, tophenylene diisocyanate, p-phenylene diisocyanate, naphthalene-1,5-diisocyanate or 3,3°-dimethyldiphenyl-4,4′-diisocyanate, and diphenyl ether-2,4,4 Triisocyanates such as '-triisocyanate can be mentioned, and only one type of these can be used, and
Two or more types can also be used in combination.

In addition, the polyol used together with this polyisocyanate is a compound having at least two or more hydroxyl groups,
For example, ethylene glycol, propylene glycol,
Diols such as butylene glycol, triols such as glycerin, polyhydric alcohols such as pentaerythritol, methyl glucoside, sorbitol, alkylene oxide addition compounds of these diols, triols and polyhydric alcohols, Alkanolamines such as jetanolamine and triethanolamine, alkylene oxide addition compounds of these alkanolamines, alkylene addition compounds of polyamines, or polyesters produced from dicarboxylic acids or their acid anhydrides and glycols, etc. can be mentioned. These polyols can be used alone or in combination of two or more.

In the present invention, it is essential that the blending ratio of the polyisocyanate and polyol is such that the ratio of isocyanate groups in the polyisocyanate to hydroxyl groups in the polyol (NGOloH') is within the range of 0.7 to 1.5. , preferably within the range of 0.9 to 1.2. When the NGO10H ratio is smaller than 0.7 and larger than 1.5, the mechanical strength of the rigid foam product decreases, making it impossible to use it for applications such as building materials that particularly require strength.

Furthermore, as the blowing agent used with these polyisocyanates and polyols, blowing agents used in the production of ordinary polyurethane foams can be used, such as water, pentane, hexane, heptane, pentene, Examples include low-boiling hydrocarbons such as benzene, and low-boiling halogenated hydrocarbons such as dichlorodifluoromethane, dichlorodifluoroethane, cyclofluoromethane, isopropyl chloride, and methylene chloride.

As the isocyanate group polymerization catalyst used as a catalyst during polymerization, isocyanate group polymerization catalysts used in the production of ordinary polyurethane foam can be used, such as sodium phenolate, sodium trichlorophenolate, etc. sodium phenolates and 2゜4.6-tri(dimethylaminomethyl)
-phenol, 0-dimethylaminomethylphenol,
Examples include phenols such as trimethylaminomethylphenol.

Furthermore, as flame retardants used for the purpose of improving flame retardancy, flame retardants used for hard polyurethane and tanform can be used, such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, etc. Inorganic hydroxides, organic phosphorus esters such as tris-β-chloroethyl phosphate and tris-dilibrovir phosphate, and reactive non-reactive compounds such as chlorendic acid anhydride, phosphorus atom-containing polyols, and bromine atom-containing polyols. Refueling agents, ammonium phosphate, etc. can be mentioned, but inorganic hydroxides are preferred, and one or more kinds selected from aluminum hydroxide, calcium hydroxide, and magnesium hydroxide are more preferred. It is a mixture. This flame retardant can be blended by being mixed in advance with polyisocyanate and/or polyol, preferably polyol, or it may be added during polymerization and foaming and blended so as to be uniformly dispersed. .

Furthermore, as the foam stabilizer used together with each of the above-mentioned ingredients, conventionally known foam stabilizers for polyurethane foam, such as tributyl phosphate, silicone emulsion,
-Ethylhexyl alcohol etc. can be used,
Preferably it is a silicone oil such as polymethylsiloxane. It is desirable that this foam stabilizer is mixed in advance with both or one of the polyisocyanate and the polyol.

Regarding the blending ratio of the isocyanate copolymerization catalyst, blowing agent, flame retardant, and foam stabilizer, the isocyanate copolymerization catalyst is 1 part by weight per 100 parts by weight of the polyisocyanate.
~15 parts by weight, preferably 5 to 10 parts by weight, a blowing agent of 5 to 50 parts by weight, preferably 10 to 30 parts by weight, and a flame retardant of 60 to 200 parts by weight, preferably 100 to 100 parts by weight.
In addition, the foam stabilizer is 1 to 10 parts by weight, preferably 3 to 7 parts by weight. Regarding the blending ratio of the isocyanate copolymerization catalyst, if it is less than 1 part by weight, the polymerization reaction will be insufficient, and if it is more than 15 parts by weight, the reaction will be too rapid and production will be difficult. Regarding the mixing ratio of the blowing agent, if it is less than 5 parts by weight, foaming will be insufficient, and if it is more than 50 parts by weight, the reaction itself will be adversely affected. Furthermore, regarding the blending ratio of the flame retardant, if it is less than 60 parts by weight, the flame retardant performance will be insufficient, and if it is more than 200 parts by weight, the foam will become brittle and cannot be used. Regarding the blending ratio of the foam stabilizer, if it is less than 1 part by weight, the cells will become rough and uneven, and if it is more than 10 parts by weight, the adhesive strength with the surface material will be reduced.

The method for producing the rigid foam of the present invention using the above-mentioned ingredients is not particularly limited, and includes conventionally known methods such as the stock solution mixing method, pure one-shot method, premix method, Examples include the pure prepolymer method and the semi-prepolymer method, and also the non-70s method and the 70s method depending on the discharge state of the mixed stock solution.

[Effect]

The rigid foam of the present invention is produced by blending the polyisocyanate and polyol used as raw materials so that the ratio of isocyanate groups to hydroxyl groups (NGOloH) is within the range of 0.7 to 1.5, and then By adding a foaming agent to foam and adding a flame retardant, it not only has excellent heat insulation and flame retardant properties, but also forms a foam consisting of uniform, fine-grained, high-quality cells, and has excellent mechanical strength. It is thought that it will demonstrate.

〔Example〕

Hereinafter, the rigid foam of the present invention will be specifically explained based on Examples and Comparative Examples.

Examples 1 to 6 and Comparative Examples 1 to 4 As the polyisocyanate, Toyo Tire & Rubber Industries (trade name: Soflan R-XK-23-1, PA) was used.

-23-2-A is used in Soflan R-X manufactured by Toyo Tire & Rubber Industries, which contains a catalyst and a blowing agent in advance as a flame retardant, and aluminum hydroxide, magnesium hydroxide, or calcium hydroxide is used as a flame retardant. Furthermore, using silicone oil (Toshi Silicone 5H-193) as a foam stabilizer, a foam stock solution having the composition shown in Table 1 was prepared,
This foam stock solution was polymerized and foamed according to a conventional method, and this was sandwiched between color steel plates with a thickness of 0.511 mm to form a 42 mm thick foam.
JIl sandwich panel is made, and for this sandwich panel, the area surrounded by temperature and time ('C, 1
n, ), flame retardancy evaluated by smoke emission coefficient and afterflame time (sec,
El-1621) and tensile strength (*g/cj, AST
The mechanical strength indicated by HD-1623) was investigated.

The results are shown in Table 1.

(Effect of publication) The rigid foam of the present invention is applicable to Ministry of Construction Notification No. 1 and 2 of 1976.
Not only does it exhibit excellent heat insulation and flame retardancy that fully satisfies the flame retardant regulation values stipulated in No. 31, but at the same time,
It has a form consisting of uniform, fine-grained, high-quality cells, and exhibits excellent mechanical strength to the extent that it can be used in building materials that require strength.

Patent applicant: Nippon Light Metal Co., Ltd. Representative: Patent attorney: Tomohiro Nakamura (2nd year)
given name)

Claims (3)

[Claims] (1) Ratio of isocyanate groups to hydroxyl groups (NCO/OH
) is within the range of 0.7 to 1.5, an isocyanate copolymerization catalyst, a blowing agent, a flame retardant, and a foam stabilizer are coexisted. Flame retardant rigid foam. (2) The heat-insulating and flame-retardant rigid foam according to claim 1, wherein the flame retardant is one or a mixture of two or more selected from aluminum hydroxide, calcium hydroxide, and magnesium hydroxide. (3) The heat-insulating and flame-retardant rigid foam according to claim 1 or 2, wherein the foam stabilizer is a foam stabilizer for urethane foam.