阅读说明：本技术 一种酚醛树脂木材增韧胶黏剂的制备方法 (Preparation method of phenolic resin wood toughening adhesive ) 是由 张蒙 马韵升 冯冶 韩文攀 李双昌 柳金章 于 2019-11-11 设计创作，主要内容包括：本发明提供了一种酚醛树脂木材增韧胶黏剂的制备方法,包括将熔融苯酚、酸性催化剂、烯烃混合,反应得到混酚反应液；将混酚反应液中酸性催化剂过滤或者加入碱性化合物中和；再与碱性催化剂混合、保温活化,加入甲醛水溶液,保温反应,得到反应产物；将反应产物与水混合得到酚醛树脂木材增韧胶黏剂。本发明以苯酚和烯烃为原料,在酸性催化剂作用下通过烷基化反应得到少量烷基化苯酚与苯酚的混酚反应液,再与甲醛进行加成、缩合,得到增韧改性的水溶性酚醛树脂产品。本发明合成了木材增韧胶黏剂,使用该胶黏剂得到的基材产品冲击韧性、抗拉强度等性能明显提升。本方法制备增韧胶黏剂,节约了成本、能耗,提高了胶黏剂和木材产品的性能。(The invention provides a preparation method of a phenolic resin wood toughening adhesive, which comprises the steps of mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution; filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product; and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive. The invention takes phenol and olefin as raw materials, obtains a small amount of mixed phenol reaction liquid of alkylated phenol and phenol through alkylation reaction under the action of an acid catalyst, and then carries out addition and condensation with formaldehyde to obtain a toughened and modified water-soluble phenolic resin product. The wood toughening adhesive is synthesized, and the properties of a base material product obtained by using the adhesive, such as impact toughness, tensile strength and the like, are obviously improved. The method for preparing the toughening adhesive saves cost and energy consumption, and improves the performances of the adhesive and wood products.)

1. A preparation method of a phenolic resin wood toughening adhesive is characterized by comprising the following steps:

A) mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution;

B) filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product;

C) and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive.

2. The method according to claim 1, wherein the olefin is one selected from the group consisting of 1-butene, 1-hexene, 1-octene, butadiene, and isoprene.

3. The method according to claim 2, wherein the molar ratio of the olefin to the phenol is 0.02:1 to 0.1: 1.

4. The method according to claim 1, wherein the acidic catalyst is selected from the group consisting of concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, strongly acidic ion exchange resins, perfluorosulfonic acid resins, aluminum trichloride and iron trichloride.

5. The preparation method according to claim 1, wherein the amount of the acidic catalyst is 0.02 to 0.15 wt% based on the mass of phenol.

6. The preparation method according to claim 1, wherein the reaction temperature in the step A) is 100-150 ℃; the reaction time is 0.5-2 h; the reaction is carried out under inert gas conditions.

7. The preparation method according to claim 1, wherein the alkaline catalyst is selected from sodium hydroxide, potassium hydroxide or barium hydroxide, and the molar ratio of the alkaline catalyst to phenol is 0.15: 1-0.22: 1.

8. The preparation method according to claim 1, wherein the temperature for the heat preservation and activation in the step B) is 40-60 ℃.

9. The method according to claim 1, wherein the molar ratio of phenol to formaldehyde is 1: (1.2-2.5).

10. The preparation method of claim 1, wherein the temperature of the heat preservation reaction in the step B) is 70-90 ℃, and the reaction time is 2.5-5 h.

Technical Field

The invention relates to the technical field of adhesives, in particular to a preparation method of a phenolic resin wood toughening adhesive.

Background

The phenolic resin has the characteristics of high mechanical strength, good electrical insulation performance, flame retardancy and the like, has a large modification scope, and is widely used for preparing glass fiber reinforced plastics, molding compounds, coatings, adhesives and the like. However, phenolic resins also have the disadvantage that the cured phenolic resin is brittle because the aromatic nuclei are linked only by methylene groups. For phenolic resin wood adhesives, the mechanical properties of wood are greatly influenced by too much brittleness, so that new requirements are provided for high-performance phenolic resin along with the development of the industry, and the requirements cannot be met by pure phenolic resin. In order to improve the performance of the phenolic resin and expand the application range of the phenolic resin, the toughening and modification of the phenolic resin are imperative.

In recent decades, much work has been done on the modification of phenolic resins, where the addition of elastomers, thermoplastic resins or the introduction of flexible groups is the main means of toughening. The alkylphenol has certain toughness due to the existence of the alkyl, so that the brittleness of the phenol phenolic resin can be improved by replacing a part of the alkylphenol with the phenol, and the toughness of the phenolic resin is improved. The alkylphenol is high in price, so that the cost of the phenolic resin is increased, the raw material for preparing the alkylphenol is phenol, therefore, the phenol is considered as the raw material, the olefin is taken as an alkylating reagent, the alkylation reaction is carried out, a small amount of phenol is alkylated to obtain alkylated phenol, and the reaction mixture is subjected to simple treatment and then continuously reacts with formaldehyde to synthesize the water-soluble toughened modified phenolic resin with the alkyl chain. The toughened and modified phenolic resin is used as a wood adhesive.

According to the invention, the raw material phenol of the phenolic resin is subjected to alkylation modification, a flexible alkyl chain is introduced, the brittleness of the phenolic resin is improved, the phenol is not required to be refined and separated after alkylation, the next step of phenolic resin adhesive synthesis is directly carried out, the condition that high-price alkylphenol is directly used as a toughening modifier is avoided, the toughness of the phenolic resin adhesive is increased, and the application range is widened.

Disclosure of Invention

In view of the above, the technical problem to be solved by the invention is to provide a preparation method of a phenolic resin wood toughening adhesive, and the phenolic resin wood toughening adhesive provided by the invention has good water solubility and good toughness.

The invention provides a preparation method of a phenolic resin wood toughening adhesive, which comprises the following steps:

A) mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution;

B) filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product;

C) and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive.

Preferably, the olefin is selected from one of 1-butene, 1-hexene, 1-octene, butadiene or isoprene.

Preferably, the molar ratio of the olefin to the phenol is 0.02:1 to 0.1: 1.

Preferably, the acidic catalyst is selected from concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, strong acid ion exchange resin, perfluorinated sulfonic acid resin, aluminum trichloride or ferric trichloride.

Preferably, the dosage of the acidic catalyst is 0.02-0.15 wt% of the mass of the phenol.

Preferably, the reaction temperature in the step A) is 100-150 ℃; the reaction time is 0.5-2 h; the reaction is carried out under inert gas conditions.

Preferably, the alkaline catalyst is selected from sodium hydroxide, potassium hydroxide or barium hydroxide, and the molar ratio of the alkaline catalyst to the phenol is 0.15: 1-0.22: 1.

Preferably, the temperature for heat preservation and activation in the step B) is 40-60 ℃.

Preferably, the molar ratio of phenol to formaldehyde is 1: (1.2-2.5).

Preferably, the temperature of the heat preservation reaction in the step B) is 70-90 ℃, and the reaction time is 2.5-5 h.

Compared with the prior art, the invention provides a preparation method of a phenolic resin wood toughening adhesive, which comprises the following steps: A) mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution; B) filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product; C) and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive. The invention takes phenol and olefin as raw materials, obtains a small amount of mixed phenol reaction liquid of alkylated phenol and phenol through alkylation reaction under the action of an acid catalyst, and then carries out addition and condensation with formaldehyde to obtain a toughened and modified water-soluble phenolic resin product which is used for wood adhesives. The wood toughening adhesive is synthesized, and compared with a base material product obtained by the original phenolic resin adhesive, the base material product obtained by using the adhesive has obviously improved properties such as impact toughness, tensile strength and the like, and the toughness of the adhesive is obviously improved. The method for preparing the toughening adhesive saves cost and energy consumption, and improves the performances of the adhesive and wood products.

Detailed Description

The invention provides a preparation method of a phenolic resin wood toughening adhesive, and a person skilled in the art can use the contents to reference the contents and appropriately improve process parameters to realize the toughening adhesive. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention provides a preparation method of a phenolic resin wood toughening adhesive, which comprises the following steps:

A) mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution;

B) filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product;

C) and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive.

The method comprises the steps of mixing molten phenol, an acid catalyst and olefin, and reacting to obtain a mixed phenol reaction solution.

The invention takes phenol as raw material and olefin as alkylating agent, and carries out partial alkylation reaction (as reaction equation 1) under the catalysis of acid, so as to synthesize a mixture containing a small amount of alkylphenol and phenol.

The method comprises the steps of putting molten phenol and an acid catalyst into a flask, stirring, heating, introducing olefin under the protection of nitrogen, and carrying out heat preservation reaction.

In the present invention, the olefin is preferably one selected from 1-butene, 1-hexene, 1-octene, butadiene or isoprene; more preferably one of 1-butene or isoprene; most preferably 1-butene.

The mol ratio of the olefin to the phenol is preferably 0.02: 1-0.1: 1; more preferably from 0.04:1 to 0.07: 1.

In order to save cost and ensure the water solubility of the phenolic resin product, the content of alkylated phenol in the mixture of alkylated phenol and phenol cannot be too large, and in order to ensure obvious toughening performance, the content of alkylated phenol cannot be too small, so the molar ratio of the olefin to the phenol in the reaction is in the specific range.

The catalyst is acid catalysts such as concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid or strong acid ion exchange resin, perfluorinated sulfonic acid resin and the like, or Lewis acid catalysts such as aluminum trichloride, ferric trichloride and the like; preferably concentrated sulfuric acid, strongly acidic ion exchange resin and perfluorosulfonic acid resin.

Wherein the dosage of the acidic catalyst is preferably 0.02-0.15 wt% of the mass of phenol; more preferably 0.08 to 0.12% wt.

The specific amount of the acidic catalyst used in the alkylation of phenol with olefin in the above reaction is to ensure the conversion rate and reaction efficiency of olefin and the conversion rate of olefin.

The present invention is not limited to the specific parameters of the stirring, and those skilled in the art will be familiar with the stirring. The reaction temperature is preferably 100-150 ℃; more preferably 110 to 140 ℃; the reaction time is 0.5-2 h; the reaction is carried out under inert gas conditions.

In order to ensure the conversion rate and the reaction efficiency of the olefin, the reaction temperature is controlled within the temperature range, the temperature is too low, the olefin self-polymerization reaction is more, and the catalyst is greatly damaged by too high temperature; in order to ensure the reaction rate of the reaction in the step and the conversion rate of the olefin.

Filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization.

After the reaction is finished, the resin catalyst is filtered out when the resin catalyst is hot, the filtrate is continuously reacted in the next step, and the filtered catalyst can be repeatedly used after being activated; if the small molecular acid catalyst used in the step A) is concentrated sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid and the like, the same molar amount of sodium hydroxide is added for neutralization after the reaction is finished.

Then mixing with alkaline catalyst, and activating by heat preservation. Namely, the mixed phenol reaction liquid is activated.

Adding an alkaline catalyst into the reaction liquid after filtration or neutralization to serve as a catalyst for polymerization reaction, keeping the temperature after adding the catalyst, activating the mixed phenol reaction liquid by the catalyst, and preferably keeping the temperature at 40-60 ℃.

The alkaline catalyst is selected from sodium hydroxide, potassium hydroxide or barium hydroxide, and the molar preferred ratio of the alkaline catalyst to phenol is 0.15: 1-0.22: 1; more preferably 0.16:1 to 0.20: 1.

After heat preservation and activation, adding formaldehyde water solution, and carrying out heat preservation reaction to obtain a reaction product.

The molar ratio of phenol to formaldehyde according to the invention is preferably 1: (1.2-2.5); more preferably 1: (1.5-2.2).

The consumption of the formaldehyde in the reaction is too small, the water solubility of the product is too large, the consumption of the formaldehyde is too much, and the free formaldehyde of the product is too high; when the formaldehyde is dropwise added, the temperature is controlled to be below 60 ℃, the formaldehyde is volatile when the temperature is too high, and the polymerization reaction can be advanced and even implosion can be caused when the temperature is too high.

After the formaldehyde is dripped, the reaction temperature can be increased to 70-90 ℃ after the temperature is stabilized, the reaction time is 2.5-5h, the reaction temperature is too high, the reaction time is long, the polymerization degree of the product is large, the molecular weight cannot well permeate into the interior of the wood, the reaction time is short, the reaction temperature is low, the molecular weight of the product is too low, the energy required by the wood during curing is high, and therefore the reaction temperature and the reaction time need to be controlled, the temperature is immediately reduced after the reaction is finished, and the material is discharged. The temperature for reducing the temperature is 25 DEG C

And mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive. And adding a proper amount of deionized water into the obtained product to prepare the adhesive with certain solid content. The mixing ratio is preferably 1: 2.

The invention provides a preparation method of a phenolic resin wood toughening adhesive, which comprises the following steps: A) mixing molten phenol, an acidic catalyst and olefin, and reacting to obtain a mixed phenol reaction solution; B) filtering the acidic catalyst in the mixed phenol reaction liquid or adding an alkaline compound for neutralization; mixing with an alkaline catalyst, performing heat preservation and activation, adding a formaldehyde aqueous solution, and performing heat preservation reaction to obtain a reaction product; C) and mixing the reaction product with water to obtain the phenolic resin wood toughening adhesive.

The method comprises the steps of introducing a small amount of olefin into phenol serving as a raw material under an acidic catalyst to perform an alkylation reaction with the phenol to generate a phenol mixture containing a small amount of alkylated phenol, treating the phenol mixture serving as a phenol raw material of phenolic resin, adding sodium hydroxide to activate the phenol mixture for a period of time, dropwise adding a formaldehyde aqueous solution, performing heat preservation reaction, gelling, cooling and discharging the product to obtain the toughened and modified phenolic resin wood adhesive. The impact strength of the wood is increased due to the fact that the alkylphenol is stronger than the common phenolic resin in toughness. Indexes of the adhesive are detected according to a wood adhesive detection method in GB/T14074-2017, and all the indexes are qualified. Phenol is used as a raw material, a small amount of alkylated phenol is obtained by phenol alkylation, the reaction mixture does not need to be refined and separated, and compared with the method of directly using the alkylated phenol as the raw material, the method reduces the cost of the raw material. According to GB/T17657-2013, the indexes such as impact toughness performance, tensile strength and the like of a wood test piece prepared from the adhesive are detected, the toughness of the wood test piece prepared from the alkylated modified phenolic resin is improved compared with that of a common phenolic resin test piece, the impact toughness of the wood test piece is improved by 26%, the tensile strength of the wood test piece is improved by 30%, the static bending strength of the wood test piece is improved by 33%, and the elastic modulus of the wood test piece is improved by 130%.

In order to further illustrate the present invention, the following describes in detail the preparation method of the phenolic resin wood toughening adhesive provided by the present invention with reference to the examples.