JPS633014A - Production of phenolic resin foam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing isocyanate-modified phenol foam.

[Prior art] Although phenol foam has excellent performance such as flame retardancy and low smoke emission, it is difficult to make -1iffl have self-adhesive properties with steel sheets compared to urethane foam and isocyanurate foam. Therefore, it is not suitable for continuous foam production of phenolic foam/steel sheet composites. Generally speaking, phenol foam has the disadvantage of slow foaming and curing speeds and poor productivity.

JP-A-59-45,332 describes a phenol foam made by adding an isocyanate compound to a benzylic ether type phenolic resin, but the foam made from the benzylic ether type phenolic resin has a low density; When used as a building material, its mechanical strength is insufficient.Additionally, a method for adding and mixing a curing agent and an isocyanate compound to a phenol resin includes a method in which both are added at the same time and mixed together.

[Problems to be Solved by the Invention] The present invention further improves the flame retardancy, which is a characteristic of phenol foam, gives it self-adhesion to steel sheets, which is its disadvantage, and makes foaming as uniform as possible. It is an object of the present invention to provide a method for injecting isocyanate-modified phenol foam, which can be carried out in a variety of ways, and which also has good mechanical strength.

[Means for Solving the Problems] That is, the present invention provides a method for forming a phenol foam by adding an isocyanate compound, a foam stabilizer, a foaming agent, and a curing agent to a resol type phenol resin. This is a method for producing isocyanate-modified phenol foam, which is characterized in that a curing agent is mixed after the compounds are mixed.

The resol type phenolic resin used in the present invention is synthesized by a known method.

For example, a phenol compound such as phenol or alkylphenol is reacted with an aldehyde such as formaldehyde in a ratio of 1:1 to 1:3 in the presence of an alkali catalyst, neutralized with an acid, and then reduced to an appropriate viscosity by dehydration under reduced pressure. Obtained by adjusting.

The viscosity of the resol type phenolic resin used in the present invention is 500 to 20. ○0Ocps, preferably 1.0
00 to 15,000 cps is used. In terms of foaming operations, lower viscosity is preferred; however, lower viscosity generally has a higher water content, which adversely affects adhesion to steel plates. The moisture content is preferably 20% or less.

The foam stabilizer used in the present invention is a silicone surfactant and/or a nonionic surfactant. The preferred amount of the foam stabilizer used is 0.5 to 10 parts by weight per 100 parts by weight of the resol type phenolic resin. The blowing agent used in the present invention is a low-boiling aliphatic hydrocarbon or its halide, and includes, for example, petroleum ether, n-hekyrin, methylene chloride, freons such as trichlorofluoromethane, and the like.

The curing agent used in the present invention can be arbitrarily selected from organic f2Ms such as benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, and phenolsulfonic acid, and inorganic acids such as hydrochloric acid. The preferred amount of curing agent used is phenol resin 10
The amount of acid is 5 to 50 parts by weight based on 0 parts by weight.

The isocyanate compound used in the present invention is preferably polymethylene polyphenylisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, etc.
An isocyanate compound having a terminal isocyanate group, which is a reaction product of polyisocyanate and a polyhydric alcohol such as glycol or glycerin, or a prepolymer type isocyanate having a terminal isocyanate group obtained by the reaction of polyisocyanate and a polyether-based or polyester-based polyol. Compounds can also be used.

The isocyanate compound is resol type phenolic resin 1
00 parts by weight, it is used in a range of 3 to 60 parts by weight.

The preferred amounts of the isocyanate compound and curing agent are determined based on the correlation with the physical properties of the foamed phenol foam, such as its self-adhesive strength with the steel plate, degree of flame retardancy, curing speed, and film strength. For example, when focusing on self-adhesive strength with a steel plate and form strength, the preferred amount of curing agent used is 15 parts or more of the curing agent based on the resol type phenolic resin (assuming the acid is 100%), but if too much is used, In the case of a composite with a steel plate, the amount is preferably 30 parts by weight or less since there is a risk of corrosion of the steel plate.

Furthermore, when considering the degree of flame retardancy, the preferred amount of the isocyanate compound to be used is 5 parts by weight or more, and when considering the curing speed, the preferred amount of the isocyanate compound to be used is 40 parts by weight.

In the present invention, in order to further improve the mechanical properties of the foam, as additives, polyhydroxy compounds such as ethylene glycol, glycerin, or nitrogen-containing compounds such as jetanolamine, It is also possible to add ethanolamine, urea, etc., and it is also possible to appropriately add flame retardants, inorganic fillers, etc. in order to further improve flame retardancy and low smoke generation properties. In addition, zinc powder or the like may be added to improve the corrosivity of the steel plate.

The foam according to the invention is produced as follows.

When mixing the isocyanate compound and the curing agent with the resol type phenolic resin, the isocyanate compound is mixed and then the curing agent is mixed. At this time, the foam stabilizer and the foaming agent may be mixed before, after, or simultaneously with the isocyanate compound or curing agent, but it is preferable to heat the mixture before mixing the isocyanate compound. In addition, the time from mixing the isocyanate compound to adding the curing agent varies depending on the temperature, but at room temperature around 20°C, after adding the isocyanate compound, the time is 3 to 180 seconds, preferably 5 to 6 seconds.
It is preferable to add the curing agent after 0 seconds. If this time is too long, gelation will occur.

If the isocyanate compound and the curing agent are mixed in the reverse order or mixed at the same time, foaming will become non-uniform and the strength of the foam will also decrease.

Examples of the mixing method include mixing using a dynamic mixer and mixing using a static mixer.

In applying the phenol form of the present invention to panels, the following methods can be cited as examples.

A resol-type phenolic resin, a foam stabilizer, a blowing agent, and other additives as the case may be are mixed. Next, a polyisocyanate compound was added to this mixed solution, and after mixing, 3 to 18
After 0 seconds, a hardening agent is added, stirred vigorously at room temperature, poured into a mold with steel plates arranged on the upper and lower surfaces of the mold, and humidified to 50 to 100°C to obtain a foam panel with steel plates. Further, by running a steel plate, continuously pouring the phenol resin mixed with a hardening agent therein and passing it through a heating chamber, one foam panel with a steel plate is continuously produced.

The steel plate used in the present invention may be a galvanized iron plate or may have its surface coated. As the paint, for example, acrylic resin paint, polyester resin paint, etc. are preferably used.

[Example] Next, the present invention will be explained in more detail with reference to Examples.

Example 1 The resol type phenolic resin used for producing the foam was Phenol 1. It was synthesized by reacting ooog and 1552 g of 37% formalin at 70° C. for 8 hours in the presence of 90 g of 33% caustic soda, neutralizing with hydrochloric acid, and dehydrating under reduced pressure. The viscosity of the resol type phenolic resin thus cracked was 10°000 CI at 25°C.

100 parts by weight of resol type phenolic resin, 2 parts by weight of foam stabilizer (L-5'340: manufactured by Nippon Unicar ■), 2 parts by weight of foaming agent
Add 0 weight W parts (Dyclone S-3: manufactured by Daikin Industries, Ltd.) and mix thoroughly, add >10 ffl parts of crude diphenylmethane diisocyanate (Millionate MR-200: manufactured by Nippon Polyurethane Co., Ltd.), and use a lab mixer. After stirring and mixing vigorously for 3 seconds at 9,000 to 10.00 rpm, add a curing agent (66.7% para-toluenesulfonic acid aqueous solution > 30 parts) and mix with a lab mixer for 9 seconds.
．． 000-10. Stirred at OOOrpm for 20 seconds.

Next, straighten this to 30cm x 30cm x 1, 5c
The mixture was poured into a No. m mold, and heated and foamed in an oven at 90'C for 5 minutes to harden it.

Examples 2 to 5 Experiments similar to those in Example 1 were conducted under the conditions shown in Table 1. In addition, in Example 5, a static mixer (10 elements and 25 elements) was used instead of a lab mixer. The conditions and results are shown in Table 1.

Comparative Examples 1-2 Except for mixing the isocyanate compound and the curing agent at the same time,
An experiment similar to Example 1 was conducted. In Comparative Example 2, a static mixer (35 elements) was used instead of the lab mixer. The mixing time was 20 seconds in Comparative Example 1 and 3 seconds in Comparative Example 2. Other conditions and results are shown in Table 1.

Table 1 (Note) The appearance of the foam is as follows: ◎: Foaming is uniform and good appearance, O
Evaluation was made on a three-level scale:: good foam, and X: uneven foaming.

[Effects of the Invention] According to the present invention, continuous foam production is possible due to self-adhesiveness with steel plates, and foaming can be performed as uniformly as possible, resulting in good appearance and mechanical strength. The phenol form is obtained.

Flame retardancy and low smoke emission are also improved.

Claims (2)

[Claims] (1) In the method of forming phenol foam by adding an isocyanate compound, a foam stabilizer, a foaming agent, and a curing agent to a resol type phenolic resin, the curing agent is mixed after the isocyanate compound is mixed with the resol type phenolic resin. A method for producing an isocyanate-modified phenol foam, characterized by: (2) The method for producing phenol foam according to claim 1, wherein a curing agent is mixed after an isocyanate compound is mixed with a phenol resin mixed with a foam stabilizer and a blowing agent.