Low-temperature fast-curing resin composition

Abstract

To provide a resol resin composition that quickly hardens at 120°C, which is a relatively low temperature to harden a resol resin.SOLUTION: A resol resin composition comprises magnesium nitrate dissolved in a resol resin comprising water. The magnesium nitrate of 0.1-10 pts.mass is dissolved in the resol resin of 100 pts.mass which comprises water.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resole resin composition that cures quickly at 120°C, which is a relatively low temperature range for curing resole resins. [Background technology]

[0002] Phenolic resins have good resistance to heat, acids, alkalis, and oils, and are therefore used in a variety of fields, including various molded products, cores for automobile engines, curing agents for epoxy resins used to secure semiconductor components, photoresist materials, and adhesives for plywood.

[0003] Phenolic resins are broadly classified into resol resins, which are produced using an alkaline catalyst, and novolac resins, which are produced using an acid catalyst. Resole resins contain methylol groups, and when heated, the methylol groups react with aromatic rings to form methylene bonds, or the methylol groups condense with each other to form dimethylene ether bonds.Through this reaction, three-dimensional crosslinking occurs, increasing the hardness of the composition, so this is generally referred to as curing (reaction).To speed up the curing process and obtain a harder cured product, acidic curing catalysts are often used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 3-140332 [Patent Document 2] Patent Publication No. 2010-170943

[0005] Recently, environmental issues have been widely recognized as a major social issue in the international community. As a solution, many developments using materials derived from natural products are being carried out. In contrast to this approach, attempts are being made to reduce power consumption as a solution to environmental issues. To achieve this, it is necessary to complete the process at lower temperatures and in shorter times.

[0006] In Patent Document 1, the curing reaction is carried out at 150° C., a temperature generally used for curing resol resins. Although the curability at 150° C. is improved compared to when no acidic curing catalyst is added, there is still room for improvement in the relatively low temperature range for curing resol resins, such as 120° C. Patent Document 2 is a publication relating to a negative electrode material for lithium-ion secondary batteries using a non-aqueous electrolyte and a method for producing the same. It shows an example of curing a slurry of Mg-Si composite powder and resol resin, but like Patent Document 1, there is room for improvement in the relatively low temperature range of 120°C for curing resol resin. Summary of the Invention [Problem to be solved by the invention]

[0007] The purpose of curing resol resins is to obtain a resol resin composition that cures quickly at a relatively low temperature of 120°C. [Means for solving the problem]

[0008] As a result of extensive research, the inventors have been able to provide a resole resin composition in which magnesium nitrate is dissolved in a resole resin containing water, characterized in that 0.1 to 10 parts by mass of magnesium nitrate alone is dissolved per 100 parts by mass of the resole resin containing water. [Effects of the Invention]

[0009] This resole resin composition cures quickly at a relatively low temperature range, such as 120°C, which reduces the burden on the environment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An example of a resol resin composition is shown below.

[0011] As mentioned above, resol resins are obtained by reacting phenols with aldehydes in the presence of an alkali catalyst.

[0012] Examples of phenols that can be used in the resol resin of the present invention include phenol, cresol, xylenol, nonylphenol, para-tertiary-butylphenol, para-secondary-butylphenol, naphthol, catechol, hydroquinone, methylhydroquinone, and dimethylhydroquinone. These phenols may be used alone or in combination.

[0013] The aldehydes used in the resol resin of the present invention can be any aldehyde that can be used in the production of resol resins. For example, formaldehyde, paraformaldehyde, trioxane (metaformaldehyde), etc. can be used alone or in combination of two or more. The preferred aldehyde is 37% formaldehyde or 92% paraformaldehyde. The amount of 37% formaldehyde added is 100 to 300 parts by mass, more preferably 150 to 250 parts by mass, and the amount of 92% paraformaldehyde added is 40 to 150 parts by mass, more preferably 50 to 100 parts by mass, per 100 parts by mass of the phenol.

[0014] The alkaline catalyst used in the reaction of phenols and aldehydes in the resole resin of the present invention is not particularly limited, and examples of alkaline catalysts that can be used include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, magnesium hydroxide, trimethylamine, triethylamine, tributylamine, and diethylethanolamine. These alkali catalysts may be used alone or in combination. The amount of the alkali catalyst added is 1 to 25 parts by mass, more preferably 2 to 20 parts by mass, per 100 parts by mass of the phenols.

[0015] The method for reacting a phenol with an aldehyde is not particularly limited, and examples thereof include a method in which a phenol, an aldehyde, and an alkali catalyst are charged all at once and reacted together, or a method in which a phenol and an alkali catalyst are charged and then an aldehyde is added at a predetermined reaction temperature. In this case, the reaction temperature is 50 to 130°C, more preferably 60 to 100°C. A temperature below 50°C is undesirable because the reaction proceeds slowly and unreacted phenols remain, while a temperature above 110°C is undesirable because it promotes the formation of high molecular weight components. There is no particular limitation on the reaction time, which may be adjusted by adjusting the amounts of aldehydes and alkali catalyst, and the reaction temperature. The molecular weight can be adjusted by controlling the reaction temperature and reaction time.

[0016] The reaction of the resole resin of the present invention can be stopped by cooling, but it can also be stopped by adding a neutralizing agent, which is an acidic component. Examples of neutralizing agents include sulfamic acid, boric acid, phosphoric acid, oxalic acid, hydrochloric acid, sulfuric acid, acetic acid, benzoic acid, methanesulfonic acid, and paratoluenesulfonic acid. The reaction can be stopped by adding 1 to 10 parts by mass, more preferably 3 to 7 parts by mass, per 100 parts by mass of phenols.

[0017] The resole resin of the present invention can be added with urea and urea derivatives as scavengers for unreacted formaldehyde, such as urea, ethylene urea, butyl urea, carbohydrazide, 1,1-dimethyl urea, 1,1-diethyl urea, cyanoacetyl urea, cyclohexyl urea, acetyl urea, allyl urea, 1,3-diallyl urea, apronal, benzoylene urea, benzoyl urea, benzyl urea, and 1,3-(hydroxymethyl) urea. The amount of urea or urea derivative added per 100 parts by weight of phenols is 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, to sufficiently scavenge unreacted formaldehyde. The scavengers for unreacted formaldehyde can be added either before the reaction begins or after the reaction has stopped.

[0018] The solid content of the resol resin of the present invention is 50 to 99% by mass, more preferably 60 to 90% by mass. When the solid content of the resol resin is high, it can be diluted by adding water. When the solid content of the resol resin is low, it can be concentrated by evaporating water.

[0019] The resole resin composition of the present invention contains magnesium nitrate, and the amount of magnesium nitrate added is 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, in terms of magnesium nitrate alone (excluding water of crystallization), per 100 parts by mass of the resole resin containing water. Magnesium nitrate exists as a hexahydrate. Either magnesium nitrate or magnesium nitrate hexahydrate can be used. The molecular weight of magnesium nitrate is 148.3, and that of magnesium nitrate hexahydrate is 256.4.

[0020] The present invention will be described in more detail below with reference to examples, comparative examples, test examples, etc., but these are given as specific examples and are not intended to limit the scope of the present invention. [Example]

[0021] <Method for producing resol resin 1> 100 g of phenol and 130 g of 37% formaldehyde were weighed into a separable flask. A lid and stirring spring were attached, and when the temperature reached 40°C, 12 g of 25% sodium hydroxide was added. The temperature was raised to 85°C and the reaction was allowed to proceed for 2 hours. After cooling to 50°C, 2 g of urea, a formaldehyde scavenger, was added and the mixture was stirred and mixed at 50°C for 30 minutes to react with the unreacted formaldehyde. 10 g of ethylene glycol was then added, and the mixture was vacuum dehydrated to remove 90 g of water. This was designated resol resin 1. The solids content was 78%.

[0022] <Method for producing resol resin 2> 100 g of phenol and 80 g of 92% paraformaldehyde were weighed into a separable flask. A lid and stirring spring were attached, and when the temperature reached 40°C, 15 g of triethylamine and 2 g of barium hydroxide were added. The temperature was raised to 75°C and the reaction was allowed to proceed for 3 hours. 13 g of urea, an unreacted formaldehyde scavenger, was added, and the mixture was stirred and mixed at 60°C for 1 hour to react with the unreacted formaldehyde. The mixture was then cooled to 30°C and neutralized with phenolsulfonic acid. 50 g of water was removed by vacuum dehydration. This was designated resol resin 2. The solids content was 75%.

[0023] <Method for producing resol resin compositions of Examples 1 to 10> To 100 g of resol resin 1, 1 g, 3 g, 5 g, 7 g, and 10 g of magnesium nitrate hexahydrate were added and homogenized to prepare liquids, which were used as resol resin compositions for Examples 1, 2, 3, 4, and 5. To 100 g of resol resin 2, 1 g, 3 g, 5 g, 7 g, and 10 g of magnesium nitrate hexahydrate were added and homogenized to prepare liquids, which were used as resol resin compositions for Examples 6, 7, 8, 9, and 10. The values in parentheses in Tables 1 and 3 indicate the amount of magnesium nitrate alone, excluding water of crystallization.

[0024] <Methods for producing resol resin compositions of Comparative Examples 1 to 12> Resol resin 1 and resol resin 2 were used as the resol resin compositions of Comparative Examples 1 and 7, respectively. 1 g, 3 g, 5 g, 7 g, and 10 g of nickel nitrate hexahydrate were added to 100 g of resol resin 1, and the resulting homogenized liquids were used as the resol resin compositions of Comparative Examples 2, 3, 4, 5, and 6. 1 g, 3 g, 5 g, 7 g, and 10 g of magnesium nitrate hexahydrate were added to 100 g of resol resin 2, and the resulting homogenized liquids were used as the resol resin compositions of Comparative Examples 8, 9, 10, 11, and 12.

[0025] <Gel time measurement method> The rate of cure was determined by measuring the gel time. Place 1.0 g of the sample to be measured on a hot plate adjusted to 120±1.0°C and start the stopwatch. Use a spatula 200 mm long, 20 mm wide, and 0.6 mm thick to spread the sample into an approximately 5 cm square. Then, press the spatula about 3 cm from the tip onto the hot plate and stroke it back and forth as if stirring. Continue the above procedure until a string forms between the hot plate and the spatula. When the sample no longer forms a string, stop the stopwatch and record this time as the 120°C gel time. The results of the Examples are shown in Tables 1 and 3, and the results of the Comparative Examples are shown in Tables 2 and 4.

[0026] Comparative Examples 1 and 7, which did not contain curing catalysts such as magnesium nitrate or nickel nitrate, had much slower gel times than those containing curing catalysts. For both resol resin 1 and resol resin 2, those containing magnesium nitrate as a curing catalyst had faster gel times than those containing nickel nitrate, demonstrating that magnesium nitrate is a better curing catalyst than nickel nitrate.

[0027] [Table 1]

[0028] [Table 2]

[0029] [Table 3]

[0030] [Table 4]

Claims

[Claim 1] A resole resin composition in which magnesium nitrate is dissolved in a resole resin containing water, characterized in that 0.1 to 10 parts by mass of magnesium nitrate alone is dissolved per 100 parts by mass of resole resin having a solid content including water of 50 to 99% by mass.

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