JPH0463912B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a sealing material with excellent waterproof properties, and more particularly to a soft to semi-rigid open-cell polyurethane foam sealing material with excellent waterproof properties. (Prior Art) Conventionally, as a waterproof foam sealing material, one in which polyurethane foam is impregnated with a waterproofing material such as asphalt is known. The polyurethane sealing material can be produced by (1) cutting an open-cell polyurethane foam to an appropriate thickness, impregnating it with a volatile solution of asphalt, and then drying it; (2) the method of (1) above. It was produced by using asphalt suspension water instead of a volatile asphalt solution. Both of the above methods (1) and (2) involve impregnation and drying steps, which not only make the operations cumbersome and have poor productivity, but also require that the foam cell size and air permeability of the open-cell polyurethane foam be sufficiently large. If not,
It is not possible to uniformly impregnate the inside with Alfalto,
Furthermore, if the foam itself is large, it has the disadvantage that it is difficult to impregnate the inside with asphalt. Furthermore, method (1) requires a large amount of volatile solvent to dissolve asphalt, which poses the risk of air pollution, harm to the human body, and flames.
Solvent drying takes a long time and productivity is poor; it stains the mating material during use or becomes sticky when handled; it is also highly sensitive to temperature, its hardness decreases in summer, and it does not recover after compression. There were many problems such as slow speed. In addition, although method (2) above can overcome the disadvantages of method (1) due to the use of volatile solvents, it takes a long time to dry, has poor productivity, and does not suspend asphalt. This requires the use of a surfactant, and this surfactant remains in the sealant even after drying and is activated when it comes into contact with water, which has the drawback of reducing waterproof properties. The present inventors first conducted research to eliminate the drawbacks of conventional methods, and found that (1) the boiling point at normal pressure is 200°C or higher;
(2) When a substance consisting essentially of hydrocarbons with a melting point or softening point of 150°C or less is mixed into a polyurethane raw material and the air permeability is below a certain level, it can be used as a waterproof sealing material. It has been found that waterproof properties can be improved when polydiene polyols, dimer acid polyols, and castor oil polyols are used alone or as a mixture thereof. As a result, it was possible to eliminate the disadvantage of necessarily impregnating fillers such as asphalt through post-treatment, and it was also possible to obtain a sealing material with excellent waterproof properties. (Problems to be Solved) As a result of various studies conducted by the present inventors on a method for producing a sealing material made of polyurethane foam that has good waterproofness and breathability, the present inventors found that
When manufacturing polyurethane foam, it was discovered that the combination of the foam stabilizer and polyol used has a great effect on the waterproofness (water leakage resistance) of polyurethane foam, and the present invention was completed. An object of the present invention is to provide a method for manufacturing a soft to semi-rigid open-cell polyurethane foam sealing material that is breathable and has excellent waterproof properties. (Means for Solving the Problems) The gist of the present invention is to provide a method for producing an open-cell polyurethane foam sealing material by reacting a polyol and a polyisocyanate in the presence of a foam stabilizer and a foaming agent. As the polyol component, at least one selected from the group consisting of polydiene polyols, dimer acid polyols, castor oil polyols, and polyether polyols obtained by addition polymerization of 90 mol% or more of alkylene oxide having 3 or more carbon atoms, In addition, as the foam stabilizer, a compound having _the general formula R ₃ SiO(-SiR ₂ O( _- (where x represents an integer.) A soft or semi ^- hard material characterized by using an organosilicon compound having A method for producing an open-cell polyurethane foam sealant. That is, the present invention provides a method for producing a polyurethane foam sealant by combining a specific polyol component and the silicone compound as a foam stabilizer. , 10mm thickness air permeability 20
It is possible to produce a polyurethane foam sealing material that has good waterproof properties while having air permeability of cc/cm ² /sec or less. The present invention will be explained in detail. In the present invention, the polyols used are polyether polyols, polydiene polyols, dimer acid polyols, and castor oil polyols. As polyether polyol, carbon water is 3
It is preferable to use addition polymerization of 90 mol% or more of the above alkylene oxides. Examples include polyhydric alcohols such as ethylene glycol, glycerin, and trimethylolpropane, and addition polymerization of alkylene oxides or allyl oxides such as propylene oxide, butylene oxide, and styrene oxide to these polyhydric alcohols. However, it is not limited to this, and these can be used alone or as a mixture, and when addition polymerizing ethylene oxide, the amount added is
It needs to be less than 10 mol%; if it exceeds this, the waterproofness will deteriorate, which is not preferable. Polydiene polyols include homopolymers or copolymers of diene compounds such as butadiene, isoprene, and chloroprene, or radical or anionic copolymers of these monomers and copolymerizable vinyl compounds such as styrene and acrylonitrile. Examples include hydroxyl group compounds, decomposition products of solid rubber containing diene components, and the like. However, the invention is not limited thereto, and these can be used alone or as a mixture. Dimer acid is a dibasic acid with double the molecular weight obtained by dividing two monobasic fatty chains (usually with 18 carbon atoms) into two halves through a carbon-carbon covalent bond. Says acid. Typical compounds thereof are obtained by heating linoleic acid and oleic acid, and their structural formulas are as follows. In addition to dimer acid, the industrial method for producing dimer acid includes monomer acid, tribasic acid, and polymeric acid. Mixtures of these may also be used in the present invention. Dimer acid derivative polyols include dimer acid polyesters, which are the reaction products of dimer acids and short-chain diols, triols, or polyols; reaction products of dimer acids and polyalkylene glycols, polyalkylene triols, or long-chain polyols; Reaction products obtained by reacting a mixture of dimer acid and other polycarboxylic acids such as adipic acid with the various diols, triols, or polyols; Reaction products of dimer acid and alkylene oxide, or mixtures thereof. However, it is not limited to this. Examples of castor oil derivative polyols include:
Castor oil polyester; polyester obtained from mixed polycarboxylic acid of castor oil and other acids such as adipic acid; castor oil and ethylene glycol,
Reaction products of short-chain polyol mixtures such as 1,4-butanediol and glycerin with polycarboxylic acids; reaction products of castor oil and alkylene oxides such as propylene oxide, ethylene oxide, butylene oxide, etc.; alkylene oxides of castor oil polyesters Mention may be made of addition polymers or mixtures thereof. However, it is not limited to this. In these dimer acid-based or castor oil derivative polyols, the number average molecular weight of castor oil is approximately 600.
~10,000, preferably 700-5,000. If it is a reaction product of dimer acid and short chain diol or triol, the number average molecular weight is 600 to 5000,
In particular, it is preferably 800 to 5000. In addition, in the case of the reaction product of dimer acid or castor oil and alkylene oxide, the number average molecular weight is
It is preferably 1000 to 5000. These average functional groups are from 1.6 to 4.5, preferably from 1.8 to 3.0. These polyols may be used alone or in combination, and other general-purpose polyether polyols or polyester polyols may also be added. The percentage of general-purpose polyol is the total polyol
It is necessary that the amount is 80 parts by weight or less per 100 parts by weight. Examples of polyisocyanate compounds include:
Examples include tolylene diisocyanate, polymethylene polyethylene polyisocyanate, hexamethylene diisocyanate, 1.5-naphthalene diisocyanate, xylylene diisocyanate, and hydrogenated polymethylene polyphenylene diisocyanate. These may be used alone or in mixtures. However, it is not limited to this.
Among these, the waterproof property is particularly improved when polymethylene polyphenylene polyisocyanate is used. The silicon compound used as a foam stabilizer has _the general formula R ₃ SiO(-SiR ₂ O( _- x represents an integer).It is known that organosilicon compounds are effective as foam stabilizers for polyurethane foams.For example, it is known that organosilicon compounds are effective as foam stabilizers for polyurethane foams for cushions. In the production of polydimethylsiloxane-polyalkylene glycol blocks and copolymer polyalkylene glycols, compounds in which the terminals of polyalkylene glycol are capped with acetyl, methoxy, ethoxy, or butoxy groups are widely used as suitable organosilicon compounds. However, when an organosilicon compound whose terminal end is capped with a group such as the one described above is used in the production of polyurethane sealants, the resulting polyurethane foam has a good foam-regulating effect, so the water content, which indicates the degree of hydrophobicity of the polymer, is The contact angle with the organosilicon compound decreased, and it became hydrophilic enough to absorb water by itself, and it was found that it could not prevent water leakage at all even under low water pressure.In contrast, organosilicon compounds represented by the general formula R It has been found that when using ₃ SiO(-SiR ₂ O(- _x SiR ₃ (in the formula, R and x represent the same as above), it becomes water repellent and can prevent water leakage under constant water pressure. The reason for these is not clear, but it is thought to be as follows.Polyurethane foam has urethane bonds, ester bonds, and urea bonds, and is highly polar and therefore hydrophilic.For example, tolylene foam Polyurethane made of isocyanate and ethyl alcohol is water-soluble, and polyether polyols such as polyethylene, polypropylene, and ether are also hydrophilic. When producing polyurethane foam, the terminals are added with acetyl, methoxy, ethoxy, or butoxy groups, etc. When using a capped organosilicon compound, the surfactant effect it has during foam regulation continues to act as an interfacial effect even after the foam is manufactured, so it has a high affinity with water, so it can be manufactured without adding these compounds. The hydrophilicity is further increased than that of the foam.An example of a comparison of waterproof properties when the organosilicon compound used in the present invention and other organosilicon compounds are used as a foam stabilizer is as follows.

[Table] However, polyol A is a polyether polyol with a molecular weight of 3000, which is made by adding propylene oxide to glycerin. Typical organosilicon compounds used in the present invention include dialkylsiloxanes such as dimethylsiloxane and diethylsiloxane, diarylsiloxanes such as diphenylsiloxane, and alkylarylsiloxanes, with dimethylsiloxane being the most preferred. usually,
A silicone oil having a viscosity of 5 to 10,000 centistokes at 25°C is used. In the present invention, when a foam is produced by mixing, as a filler, a substance substantially consisting of hydrocarbons with a boiling point of 200°C or more and a melting point or softening point of 150°C or less at normal pressure into the reaction raw material, Since the waterproof property is improved, it is preferable to mix this in order to obtain an excellent waterproof sealing material. Substances that are essentially hydrocarbons with a boiling point of 200°C or higher and a melting point or softening point of 150°C or lower at normal pressure include, for example, paraffin, waxes, coal tar, asphalt, and byproducts produced during naphtha cracking. Examples include petroleum resins made by polymerizing _C4 to _C9 fractions, petroleum-based oils such as polybutene extension oils, and the like. However, it is not limited to this. In addition to the above-mentioned fillers, waterproofness can also be improved by adding plasticizers such as dibasic carboxylic acid esters and animal and vegetable oils. Furthermore, the addition of these fillers has the effect of improving softness, increasing adhesion to contact surfaces, and reducing costs. Examples of blowing agents include water; halogens or alkanes such as monofluorinated trichlormethane and dichlorinated methane; low boiling point alkanes such as butane and pentane; azobisisobutyronitrile that generates decomposed nitrogen gas, etc. It will be done. These may be used alone or in mixtures. However, it is not limited to this. Examples of the catalyst include tertiary amines and organic tin compounds, and typical examples thereof include triethylenediamine, triethylamine, n-methylmonopholine, n-ethylmorpholine, N,N,
Examples include N',N'-tetramethylbutanediamine, stannous octoate, and stannous dibutyllaurate. However, it is not limited to this. In addition to the above, crosslinking agents used in general polyurethane foams; fillers such as carbon black and calcium carbonate; ultraviolet absorbers; antioxidants, etc. can of course be mixed and used as appropriate. The method for manufacturing the polyurethane foam sealant of the present invention uses the above-mentioned raw materials, catalysts, foaming agents, etc., and has an air permeability of 20 c.c./cm ² /
Adjust so that it is less than sec. The method of adjusting the air permeability includes the amount and type of catalyst (for example, if a tin-based catalyst is used and the amount used is large, the air permeability will be low), stirring conditions (the shape of the stirrer blades, the rotation ), the amount of dissolved air (if it is small, the air permeability will be low; if it is large, it will be high),
In addition, since it changes depending on the type and amount of the blowing agent, reaction temperature, etc., it is carried out by adjusting these. In the method for manufacturing the polyurethane foam sealant of the present invention, an open-cell foam is formed using the above-mentioned raw materials, a catalyst, a blowing agent, etc., and the manufacturing method is similar to that known in the art. (1) Prepolymer method, (2) One shot method, (3)
It can be produced by any method such as a partial prepolymer method. As mentioned above, the water leakage resistance of polyurethane foam is influenced by the type of polyurethane raw material, whether or not a waterproofing agent is added, and the type of foam stabilizer, but is also influenced by the degree of air permeability. Its air permeability is 10
The air permeability at mm thickness (hereinafter referred to as air permeability) is
At 20 c.c./cm ² /sec, the time required for water to start leaking suddenly changes and becomes longer. This relationship is shown in Figure 1. The protective properties of a polyurethane foam can be determined by measuring its contact angle with water, and it is preferred that the contact angle be at least 75 degrees or more, preferably about 90 degrees or more. The air permeability referred to herein is based on the Frangier type method of woven fabric air permeability test, and is measured with a foam thickness of 10 mm according to JIS-L-1004. The device is air permeability tester No.869 manufactured by Toyo Seiki Co., Ltd.
It was used. The above contact angle means that a foam of approximately 10 mm thickness is sandwiched between aluminum foil at a temperature of 180 to 200°C and a pressure of 40°C.
A Kyowa contact angle meter CA-A model (manufactured by Kyowa Kagaku Co., Ltd.) was used as a contact angle meter for the film that was pressed at ~50 kg/cm ² . The test for waterproofness was conducted on the outer diameter of 98 mm in length and width and the inner diameter of 68 mm in length and width as shown in Figures 2 and 3 and thickness of 10 mm.
A rectangular sample 1 of mm size is sandwiched between two acrylic plates 2 and 3, and water is injected from the water injection pipe 5 provided in the center to change the water pressure (height of the water column). When the sample 1 was sandwiched between the plates 2 and 3, the thickness of the spacer 4 was changed to change the compressibility, and the number of minutes after water was injected was measured before water started leaking. In principle, the experiment time was 60 minutes, but in some cases it was longer. When using the sealing material obtained by the method of the present invention, it is preferable that the compression ratio is 20% or more. This is because, especially in foams, the condition of the compression surface is greatly affected and it is difficult to compress the foam uniformly.
When compressed by 20%, water leakage due to the influence of the condition of the compressed surface can be prevented. Next, the present invention will be specifically explained with reference to Examples. Example 1 100 parts of a polyether polyol with a molecular weight of 3,000 obtained by addition polymerizing propylene oxide to glycerin and tolylene diisocyanate (T-65) were used as the polyol, water was used as the foaming agent, and polydimethyl was used as the foam stabilizer. The foam was prepared using siloxane (KF 96, manufactured by Shin-Etsu Chemical Co., Ltd.), triethylene diamine (Dabco-33LV) as a catalyst, and appropriate amounts of stannath octate. The waterproof properties of the obtained foams were as shown in Table 1 below. Example 2 The polyol used was a dimer acid polyester polyol (hydroxyl value 60, acid value 1.2) obtained from a dimer acid and a short chain diol instead of the polyether polyol of Example 1.
A polyurethane foam was produced in the same manner as in Example 1. The waterproofness of the obtained foam is as follows:
It was as shown in the table. Example 3 As a polyol, castor oil polyol 100 was used instead of the polyether polyol of Example 1.
A polyurethane foam was produced in the same manner as in Example 1, except that The waterproof properties of the obtained foams were as shown in Table 1 below. Example 4 As a polyol, instead of the polyether polyol of Example 1, a polybutadiene homopolymer (manufactured by Alco Chemical Co., Ltd., Poly BDR- A polyurethane foam was produced in the same manner as in Example 1, except that 100 parts of 45HT) were used. The waterproof properties of the obtained foams were as shown in Table 1 below.

[Table] (Effects) As mentioned above, the sealing material obtained by the manufacturing method of the present invention has good waterproof properties while being breathable, so it can be used under high compression. It rarely protrudes beyond the joint. for example,
When a low-permeability sealant with an air permeability of 0.1cc/cm ² /sec is compressed by 90%, the protrusion will be about 20% of the material width.
That's all. On the other hand, in the case of the sealing material according to the present invention (for example, about 20 c.c./cm ² /sec), the protrusion is about 2 to 6%. This is an advantage for applications where appearance is important. It has the following effects. Furthermore, conventional general-purpose polyurethane foams could not prevent water leakage no matter how much they were compressed, the air permeability approached zero, or the water pressure was reduced, but with the method of the present invention, water leakage could not be prevented. The resulting sealant is breathable and prevents water leakage, so it can be effectively used as a sealant for automobile fender sealers, front pillar sealers, pentilator sealers, etc., and as a sealant for ships, refrigerators, etc. It will be done.

[Brief explanation of the drawing]

Figure 1 shows the relationship between waterproofness and breathability, Figures 2 and 3 show the test pieces and test methods used in the water leakage test, Figure 2 is a plan view of the test piece, and Figure 3 shows the relationship between waterproofness and breathability. FIG. 2 is a perspective view showing the test method. 1... Test piece, 2, 3... Acrylic resin plate, 4
...Spacer, 5...Water injection pipe.

Claims (1)

[Claims] 1. A method for producing an open-cell polyurethane foam sealing material by reacting a polyol and a polyisocyanate in the presence of a foam stabilizer and a foaming agent, wherein the polyol component includes a polydiene polyol, At least one selected from the group consisting of dimer acid polyol, castor oil polyol, and polyether polyol obtained by addition polymerization of 90 mol% or more of alkylene oxide having 3 or more carbon atoms, and as the foam stabilizer, the general formula: R ₃ SiO(-SiR ₂ O(- _x SiR ₃ (wherein R represents an alkyl group such as a methyl group, ethyl group, butyl group, or an aryl group such as a phenyl group, and x represents an integer) The air permeability of 10mm thickness is 20c.c./cm ² /sec.
A method for producing a soft or semi-rigid open-cell polyurethane foam sealant, which is characterized by the following steps: 2. Substances consisting essentially of hydrocarbons with a boiling point of 200°C or higher and a melting point or softening point of 150°C or lower at normal pressure, plasticizers such as dibasic carboxylic acid esters, or animal and vegetable oils are used by mixing them with raw materials. , A method for producing a soft or semi-rigid open-cell polyurethane foam sealant according to claim 1.