JP2006152094A - Phenol resin foam and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phenol resin foam which is easy to manufacture, free from problems with storage stability and has a reduced water-absorption by subjecting the foam to water-repellent treatment. <P>SOLUTION: In the manufacturing process of the phenol resin comprising adding a foam stabilizer, foaming agent, acidic curing agent and modifier to a phenol resin followed by foaming and curing, 0.2-7 pts.wt. of a polyalkyl hydrogen siloxane expressed by general formula [1] (R is a 1-18C alkyl group) as the modifier is added to 100 pts.wt. of the phenol resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phenolic resin foam useful for applications such as heat insulating materials and flameproofing materials in the field of building materials, and more particularly a phenolic resin foam that has water repellency and low water absorption. The present invention relates to a method for producing a resin foam and a water-repellent phenol resin foam.

Phenolic resin foam is known as a heat insulating material that is superior in heat insulation, flame retardancy, heat resistance, and fire resistance compared to thermoplastic resin foam, and is used for building foam and other industries that require heat resistance. Used in the field. The phenolic resin foam is generally produced by mixing a phenolic resin, a foam stabilizer, a foaming agent, and an acidic curing agent, and foaming and curing at room temperature to 120 ° C.
These phenolic resin foams usually contain a hydrophilic hydroxyl group in the phenol resin structure, and an unreacted free acid is contained in the foam by using an acid component as a curing agent. For this reason, the resulting phenolic resin foam is hydrophilic and has a property of easily absorbing water from the surface of the foam. Under such conditions that water absorption cannot be avoided, the heat insulation performance and mechanical strength are reduced. There was concern.

  As an attempt to reduce the water absorption of a phenol resin foam, for example, a resol type phenol resin modified with at least one of diglycol of alkylene glycol or alkylene ether glycol having 2 to 6 carbon atoms and / or triglycidyl ether compound And a phenol resin foam improved in moisture absorption resistance by using an acidic catalyst containing resorcinols as a curing accelerator [see Patent Document 1].

  In this case, neopentyl glycol, 1,6-hexanediol diglycidyl ether, butyl glycidyl ether or the like is used as the glycidyl ether compound. Although these compounds are good in terms of compatibility with phenolic resins, most of them are in liquid form, so that they have low storage stability and are easily liquid-separated on a daily basis, and unreacted glycidyl ether from phenolic resin foams. Elution is likely to result in unstable product quality, and glycidyl ether may easily affect the foam curing reaction. In addition, when resorcinols are blended in an acidic catalyst, it is difficult to adjust the timing of the foam curing reaction due to the heat generated from the high reaction activity of resorcinol, and it is difficult to supply a stable phenol resin foam. it is conceivable that. Development of a phenolic resin foam having low water absorption that is stable over time has been required.

JP 59-124940 A

  The present invention relates to a phenol resin foam that is easy to manufacture, has no problem in storage stability, imparts water repellency to the obtained foam, and reduces the water absorption of the foam itself. -To provide a resin foam.

The present invention
[1] In a method for producing a phenolic resin foam in which a foam stabilizer, a foaming agent, an acidic curing agent, and a modifying agent are blended in a phenolic resin and foamed and cured, the following general formula [ 1] The polyalkylhydrogensiloxane represented by 1] is blended in an amount of 0.2 to 7 parts by weight with respect to 100 parts by weight of the phenolic resin, and a method for producing a phenolic resin foam,


R R R
｜ ｜ ｜
R—Si—O (—Si—O) n—Si—O—CH ₃ ... [1]
｜ ｜ ｜
R H R
(However, R represents a C1-C18 alkyl group.)

    [2] In a method for producing a phenolic resin foam in which a foam stabilizer, a foaming agent, an acidic curing agent, and a modifying agent are blended with a phenolic resin and foamed and cured, polyalkylhydrogensiloxane is used as the modifying agent. The above problems have been solved by developing a phenol resin foam containing 0.2 to 7 parts by weight of 100 parts by weight of phenol resin.

  In the manufacturing method of phenolic resin foam that foams and cures in the presence of phenolic resin, foam stabilizer, foaming agent, and acidic curing agent, polyalkylhydrogen siloxane is easily added as a modifier during foaming and curing reaction. Through this simple operation, the produced phenolic foam can be given water repellency and water absorption can be lowered. As a result, it has heat resistance compared to the use of other water repellents. It became possible to provide a resin foam at low cost and stably.

  The present invention produces a phenolic resin foam by blending a phenolic resin with a polyalkyl hydrogen siloxane as a modifier in order to impart water repellency to the phenolic resin foam and reduce water absorption from the foam surface. By doing so, it was obtained that the foam was given water repellency and the amount of water absorption was reduced.

Hereinafter, the present invention will be described in detail.
As the phenol resin used in the present invention, a very general phenol resin for foaming [resole type] can be used.
It is produced by reacting phenols and aldehydes with an excess of aldehydes in the presence of an alkaline catalyst, followed by dehydration and concentration.
Examples of phenols include phenol, cresol, and xylenol. Among these, phenol and m-cresol are preferable from the viewpoint of reactivity and curability. These phenols may be used alone or in combination, and may be used in combination with o-cresol, p-cresol, bisphenol and the like. As aldehydes, formaldehyde, paraformaldehyde, polyoxymethylene, trioxane and the like can be used. These aldehydes may be used alone or mixed.

Examples of the alkaline catalyst used for the production of the phenol resin include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, magnesium hydroxide and the like.
The reason why the phenol resin foam of the present invention exhibits the excellent effect is presumed as follows.

Conventionally, siloxane-based (dimethylsiloxane, dimethylpolysiloxane, polyalkylhydrogensiloxane, sodium methylsilicate, etc.), fluorine-based, paraffin-based, fatty acid-based, isocyanate-based, fat-and-oil-based, ethylene oxide-based, etc. have been used as modifiers. However, among them, in particular, a siloxane-based polyalkylhydrogensiloxane represented by the following general formula [1]


R R R
｜ ｜ ｜
R—Si—O (—Si—O) n—Si—O—CH ₃ ... [1]
｜ ｜ ｜
R H R
(However, R represents a C1-C18 alkyl group.)

It has been found that the use of can effectively reduce the surface water repellency of the phenol resin foam and reduce the water absorption of the foam.

The addition amount of the polyalkyl hydrogen siloxane is in the range of 0.1 to 7 parts by weight, preferably 0.2 to 6 parts by weight, with respect to 100 parts by weight of the phenol resin.
The polyalkyl hydrogen siloxane itself can be blended with a phenol resin, or the polyalkyl hydrogen siloxane can be blended with a phenol resin after forming an aqueous emulsion.

  The amount of polyalkylhydrogensiloxane added is 0.1 to 7 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the phenol resin. When the amount of polyalkylhydrogensiloxane added is less than 0.1 parts by weight based on 100 parts by weight of the phenol resin, sufficient water repellency cannot be obtained in the foam and low water absorption cannot be obtained. On the other hand, when the addition amount of polyalkylhydrogensiloxane exceeds 7 parts by weight, the curing is slowed down, the heat insulation performance is lowered due to the decrease in the closed cell ratio, and the appearance is deteriorated due to voids and poor curing.

  Examples of the foam stabilizer used in the present invention include surfactants such as silicone-based ethylene oxide-propyleneoxyside copolymers, or polyoxyalkylene adducts such as sorbitan, alkylphenol, and castor oil. These may be used alone or mixed, and the amount used is usually 0.5 to 10 parts by weight, preferably 0.6 to 9.5 parts by weight, based on 100 parts by weight of the phenolic resin. It is. If the amount used is less than 0.5 parts by weight, bubbles cannot be formed stably, and a homogeneous cell structure cannot be obtained (cell size variation and voids are generated). On the other hand, when the amount exceeds 10 parts by weight, the foam regulating power is excessive and the film thickness of the bubbles becomes thin, or tearing occurs and a high closed cell ratio cannot be obtained, and the effect of reducing water repellency and water absorption is not achieved.

The foaming agent is not particularly limited, and is usually used for foaming phenolic resins. In hydrocarbons, butane, n-pentane, iso-pentane, cyclopentane, 2-methylpentane, fluorohydrocarbon HFCs are used. -365mfc, HFC-245fa, etc. are used alone or in combination of two or more. The combination ratio is not particularly limited.
The amount of the foaming agent used is usually in the range of 1 to 20 parts by weight, preferably 1.5 to 15 parts by weight with respect to 100 parts by weight of the phenol resin. When the amount of the foaming agent used is less than 1 part by weight, vaporization is rapid and the foam curing cannot be balanced and a uniform cell structure cannot be obtained. On the other hand, if it exceeds 20 parts by weight, the foaming pressure in the cell and the foam regulating power cannot be balanced, the cell wall is broken, and a homogeneous cell structure cannot be obtained.

  As an additive component other than the above, an inorganic filler such as aluminum hydroxide, talc, clay, calcium hydroxide, boric acid or the like can be added to impart flame retardancy to the phenol resin. In addition, inorganic and organic fillers such as shirasu balloon, glass balloon, multi-hard aggregate, metal powder and wood powder, or fiber reinforcement such as glass fiber, carbon fiber and aramid fiber may be used in combination. .

  The phenol resin foam of the present invention is, for example, a mixture of a phenol resin, a foam stabilizer, a foaming agent, a polyalkylhydrogensiloxane as a modifier, and an acidic curing agent mixed by a high-speed stirring and mixing method. Thus, a phenol resin foam mixture is obtained. This foam mixture can be produced by foam-curing.

  Examples of the acidic curing agent used in the production of the phenol resin foam of the present invention include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, hydrochloric acid, sulfuric acid and the like. Organic acids such as inorganic acids, phenol sulfonic acids, toluene sulfonic acids, xylene sulfonic acids, aryl sulfonic acids such as benzene sulfonic acids, and alkyl sulfonic acids such as methane sulfonic acids can be used, but are not limited thereto. It is not a thing. These acidic curing agents can be used alone or in combination of two or more. Although the usage-amount of an acidic hardening | curing agent is not specifically limited, It is 1-50 weight part with respect to 100 weight part of phenol resin, Preferably it is the range of 5-30 weight part.

  EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

[Example 1]
A four-necked flask was charged with 2000 g of phenol, 2930 g of 37% formalin (formaldehyde / phenol molar ratio 1.7) and 60 g of a 20 wt% aqueous sodium hydroxide solution as a catalyst, and reacted at 80 ° C. for 2 hours. The solution was neutralized with a 15% by weight para-toluenesulfonic acid aqueous solution to pH 7.0 and subjected to dehydration under reduced pressure to obtain a resole phenolic resin having a water content of 16% by weight. The solid content was 80% by weight and the viscosity was 5000 mPas (25 ° C.). 1 part by weight of polyalkylhydrogensiloxane as a modifier, 3.5 parts by weight of a silicone-based ethylene oxide-propylene oxide copolymer as a foam stabilizer, and 100 parts by weight of a foam type phenolic resin as a foaming agent 9 parts by weight of normal pentane was added and stirred and mixed. The liquid temperature after mixing was adjusted to 0 ° C.

  Thereafter, 21 parts by weight of para-toluenesulfonic acid (60% aqueous solution) was added as an acidic curing agent at 0 ° C., and the mixture was stirred and mixed at high speed for 15 seconds with a homodisperser. The mixture was immediately poured into a 300 × 300 × 60 mm mold container heated to 75 ° C. Eight minutes after setting in the mold container, the foam was taken out, weighed, and the foam density was measured. The water repellency of the foam surface was determined by measuring the contact angle with water. The water absorption amount of the foam was measured by cutting a test piece into 100 × 100 × 25 mm and measuring the water absorption amount after immersion in 20 ° C. water for 24 hours. The results are shown in Table 1.

[Comparative Example 1]
The same procedure as in Example 1 was conducted except that the polyalkylhydrogensiloxane modifier of Example 1 was not blended.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the polyalkylhydrogensiloxane modifier in Example 1 was changed to a polydimethylsiloxane modifier.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the polyalkylhydrogensiloxane of Example 1 was changed to a paraffinic modifier.

  The present invention is based on the assumption that the water repellency can be obtained on the surface of the foam by using polyalkyl hydrogen siloxane with respect to the phenol resin. The bond between the Si-H groups of the polyalkyl hydrogen siloxane is an exothermic action during foaming. Because of the presence of water in the resin and hydrolysis in the presence of water in the resin and condensation water during foaming, polymerization occurs, and a new Si-O-Si bond is formed, and the hydrophobic methyl group is oriented. It is considered that a water repellent effect is obtained in the cross section obtained by cutting the foam. Dimethylsiloxane and polydimethylsiloxane do not have a bond between Si-CH3 groups, so that a film that forms a film and imparts water repellency is not formed, and it is considered that a water repellent effect cannot be obtained.

  The phenolic resin foam produced according to the present invention is superior in heat resistance, weather resistance, and corrosivity compared to those using other water repellents, has low water absorption, and is excellent in water repellency. Because it is a high-quality foam with little brittleness, the main applications are, for example, composite materials with aluminum plate, iron plate, kraft paper, rock wool paper, PVC leather paper, gypsum board, veneer board, corrugated paper, etc. Expected to be used in a wide range of applications such as rear ceiling boards, wall insulation (intermediate materials), fire-resistant doors that are injected and foamed into spaces such as doors, blown foam on road shoulders and tunnels, and fired carbides. it can.

Claims (2)

In the method for producing a phenolic resin foam in which a foam stabilizer, a foaming agent, an acidic curing agent, and a modifying agent are blended in the phenolic resin and foam-cured, the following general formula [1] is used as the modifying agent. The manufacturing method of the phenol resin foam characterized by mix | blending 0.2-7 weight part of polyalkyl hydrogen siloxane represented with respect to 100 weight part of phenol resin.

R R R
｜ ｜ ｜
R—Si—O (—Si—O) n—Si—O—CH ₃ ... [1]
｜ ｜ ｜
R H R
(However, R represents a C1-C18 alkyl group.)
In a method for producing a phenolic resin foam in which a foam stabilizer, a foaming agent, an acidic curing agent, and a modifying agent are blended with a phenolic resin, and the foamed and cured phenolic resin foam, polyalkylhydrogensiloxane is used as the modifying agent in phenol A phenol resin foam containing 0.2 to 7 parts by weight per 100 parts by weight of the resin.