阅读说明：本技术 一种发泡用改性酚醛树脂、发泡材料及其制备方法和应用 (Modified phenolic resin for foaming, foaming material, and preparation method and application thereof ) 是由 施晓旦 孙海强 金霞朝 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种发泡用改性酚醛树脂、发泡材料及其制备方法和应用。发泡用改性酚醛树脂的制备方法包括如下步骤：(1)造纸废弃物和弱氧化剂经混合反应,调节pH至7～12,制得改性造纸废弃物；(2)改性造纸废弃物、苯酚和甲醛经混合反应,制得物料A；(3)在pH为8～12的条件下,将物料A和甲醛经混合反应,降温,调节pH至6.5～7,即可；步骤(1)中,造纸废弃物与弱氧化剂的质量比为1：(0.06～0.1)。本发明发泡用改性酚醛树脂的制备方法提高了甲醛、苯酚和造纸废弃物之间的结合能力,降低了游离醛和游离酚的含量,制备工艺简单,甲醛的用量偏少,成本低,实现资源高度利用；制备的发泡用改性酚醛树脂粘度低。(The invention discloses a modified phenolic resin for foaming, a foaming material, and a preparation method and application thereof. The preparation method of the modified phenolic resin for foaming comprises the following steps: (1) mixing and reacting papermaking waste and a weak oxidant, and adjusting the pH value to 7-12 to obtain modified papermaking waste; (2) mixing and reacting modified papermaking waste, phenol and formaldehyde to obtain a material A; (3) under the condition that the pH value is 8-12, mixing and reacting the material A and formaldehyde, cooling, and adjusting the pH value to 6.5-7; in the step (1), the mass ratio of the papermaking waste to the weak oxidant is 1: (0.06-0.1). The preparation method of the modified phenolic resin for foaming improves the binding capacity among formaldehyde, phenol and papermaking waste, reduces the content of free aldehyde and free phenol, has simple preparation process, less formaldehyde consumption and low cost, and realizes high utilization of resources; the prepared modified phenolic resin for foaming has low viscosity.)

1. The preparation method of the modified phenolic resin for foaming is characterized by comprising the following steps:

(1) mixing and reacting papermaking waste and a weak oxidant, and adjusting the pH value to 7-12 to obtain modified papermaking waste;

(2) mixing and reacting the modified papermaking waste, phenol and formaldehyde to obtain a material A;

(3) under the condition that the pH value is 8-12, mixing and reacting the material A and formaldehyde, cooling, and adjusting the pH value to 6.5-7;

in the step (1), the mass ratio of the papermaking waste to the weak oxidant is 1: (0.06-0.1).

2. The method for producing a modified phenolic resin for foaming according to claim 1, wherein the weak oxidizing agent is Fe³⁺An oxidizing agent having an ionic oxidizing ability of an upper limit and a standard electrode potential value of less than 0.77V;

and/or in the step (1), the solid content of the modified papermaking waste is 10-80%;

and/or in the step (1), the mass ratio of the papermaking waste to the weak oxidizing agent is 1: (0.08-0.1);

and/or in the step (1), the temperature of the mixing reaction is 65-95 ℃, preferably 65-75 ℃;

and/or, in the step (1), the mixing reaction time is 20-60 min, preferably 20-30 min;

and/or in the step (1), the pH adjusting condition and method is to adjust the pH to 7-12 by using an alkaline pH adjusting agent, preferably to adjust the pH to 8.5 by using an alkaline pH adjusting agent; the alkaline pH regulator is preferably an aqueous solution of potassium hydroxide, more preferably an aqueous solution of potassium hydroxide with a mass percentage of 32%.

3. The method for preparing the modified phenolic resin for foaming according to claim 2, wherein the step (1) is carried out by adopting a programmed heating and step-by-step reaction mode, and specifically comprises the following steps: step a, mixing papermaking waste and a part of weak oxidant for reaction to prepare a material B; b, mixing the material B with the residual weak oxidant for reaction, and adjusting the pH value to 7-12 to prepare modified papermaking waste;

the weak oxidant in the step a and the weak oxidant in the step b are added dropwise; in the step a, the mixing reaction is carried out within 15-20 min, and the temperature is programmed to 65-70 ℃; in the step b, the mixing reaction is carried out within 15-20 min, the temperature is continuously programmed to 70-75 ℃ on the basis of the reaction temperature in the step a, and then the temperature is kept for 20-30 min; in the step a, the mass of the part of weak oxidizing agent accounts for 30-60% of the total mass of the weak oxidizing agent; in the step b, the percentage of the residual weak oxidizing agent in the total mass of the weak oxidizing agent is 40-70%.

4. The method for producing a modified phenol resin for foaming according to claim 1, wherein in the step (2), the mass ratio of the phenol to the paper-making waste in the step (1) is 1: (0.2 to 0.4), preferably 1: 0.3;

and/or in the step (2), the mass ratio of the phenol to the formaldehyde is 1: (0.7 to 1.5), preferably 1: (0.72 to 1.5), preferably 1: (1.08-1.5);

and/or, in the step (2), the mixing reaction time is 10-60 min, preferably 30 min;

and/or in the step (2), the temperature of the mixing reaction is 65-95 ℃, preferably 75-95 ℃;

and/or the mass ratio of the phenol in the step (2) to the formaldehyde in the step (3) is 1: (0.48 to 1), preferably 1: (0.72-1).

5. The method for preparing a modified phenolic resin for foaming according to any of claims 1 to 4, wherein in the step (3), the mixing reaction time is 30 to 90min, preferably 70 to 90 min;

and/or in the step (3), the temperature of the mixing reaction is 65-95 ℃, preferably 75-95 ℃;

and/or, in the step (3), during the mixing reaction, the pH is 8.5-9.5, preferably 9;

and/or in the step (3), during the mixing reaction, the pH is adjusted to 8-12 by adding an alkaline pH regulator; the alkaline pH regulator is preferably one or more of sodium hydroxide, potassium hydroxide, calcium oxide, magnesium oxide and zinc oxide, and is more preferably a potassium hydroxide aqueous solution;

and/or, in the step (3), the temperature is reduced to 50-70 ℃, preferably to 60-70 ℃;

and/or in the step (3), adjusting the pH value of the system to 6.5-7 by using an acidic pH regulator; the acidic pH regulator is preferably one or more of hydrochloric acid, formic acid and acetic acid, and more preferably a 30% aqueous solution of formic acid.

6. A modified phenolic resin for foaming, which is produced by the method for producing a modified phenolic resin for foaming according to any one of claims 1 to 5.

7. The modified phenolic resin for foaming according to claim 6, wherein the solid content of the modified phenolic resin for foaming is 70-90%, preferably 71.3-71.8%;

and/or the viscosity of the modified phenolic resin for foaming at 25 ℃ is 5000-12000 mPa & S, preferably 7350-9140 mPa & S;

and/or the content of free phenol and free aldehyde in the modified phenolic resin for foaming is less than 1%.

8. Use of a modified phenolic resin for foaming according to claim 6 or 7 as a starting material in the preparation of a foamed material.

9. A foamed material obtained by mixing and curing the modified phenolic resin for foaming described in claim 6 or 7, a curing agent, a surfactant and a foaming agent.

10. The foamed material of claim 9, wherein the curing agent is oxalic acid;

and/or, the surfactant is tween-80;

and/or the foaming agent is n-pentane;

and/or the mass ratio of the curing agent to the modified phenolic resin for foaming is (4-7): 100, preferably 5: 100, respectively;

and/or the mass ratio of the surfactant to the modified phenolic resin for foaming is (4-9): 100, preferably 6: 100, respectively;

and/or the mass ratio of the foaming agent to the modified phenolic resin for foaming is (4-9): 100, preferably 6: 100, respectively;

and/or the curing temperature is 60-75 ℃;

and/or the curing time is 10-15 min.

Technical Field

The invention relates to a modified phenolic resin for foaming, a foaming material, and a preparation method and application thereof.

Background

The phenolic foam plastic is named as the third generation new heat-insulating material or the heat-insulating king because the phenolic foam plastic has good flame resistance, low smoke, good high temperature resistance, stable performance, heat insulation, sound insulation, easy molding and processing and better durability. The excellent properties of low-toxicity, flame-retardant phenolic resin foams have led to the rapid development of technology development. With the increasing enhancement of human environmental awareness and resource crisis, how to effectively and comprehensively utilize biomass resources to replace petrochemical raw materials has become an increasingly hot topic and research direction.

A great deal of research is done on the application of lignin in phenolic resin at home and abroad, and some progress is made: lee in Japan uses sulfuric acid as a catalyst and phenol as a liquefier to prepare phenolic resin; in domestic Zhang wenbo, poplar bark is used as a catalyst and phenol is used as a liquefier to prepare phenolic resin; the yellow wave takes phenol as a liquefying agent and concentrated sulfuric acid as a catalyst to liquefy the walnut shell powder; zhang jin Nu and so on regard phenol as liquefier, concentrated sulfuric acid is regarded as the catalyst, liquefy bamboo powder, bamboo powder replaces 40% phenol to prepare phenolic resin A, the result finds that the viscosity of phenolic resin prepared by the above-mentioned method is all very big, its viscosity range is 20000 ~ 80000 mPas, can't foam.

Meanwhile, the traditional phenolic foam has a great problem, and the phenolic foam plastic has the defects of large brittleness, poor strength and toughness and high aperture ratio due to the large aperture diameter in the traditional phenolic foam, is easy to fall off in the using process and is easy to drop slag when being drilled and cut. In addition, the phenolic resin used for foaming has a large content of free monomers, so that the phenolic foam has a large smell and can affect the environment and human body to a certain extent in the processing and application processes. In addition, the phenolic foam has high open-cell rate and is easy to absorb water. These disadvantages limit the use of phenolic foams.

The method for improving the toughness of the phenolic foam is generally to add toughening components in the foaming process of the phenolic resin, and although the addition of various toughening components improves the toughness of the foam to a certain extent, the performances of the phenolic foam, such as flame retardance, are reduced. The addition of a large amount of toughening components can also affect the microstructure of the foam, increase the open cell ratio and the pore diameter of the foam, increase the heat conductivity coefficient and further affect the heat insulation performance of the foam.

Therefore, the development of a foamed phenolic resin with low viscosity, difficult slag falling and good mechanical properties is urgently needed in the field.

Disclosure of Invention

The invention aims to solve the technical problems of high viscosity, easy slag removal, low strength, high brittleness and the like of phenolic resin in the prior art, and provides modified phenolic resin for foaming, a foaming material, a preparation method and application thereof. The preparation method of the modified phenolic resin for foaming effectively improves the binding capacity among formaldehyde, phenol and papermaking waste, greatly reduces the content of free aldehyde and free phenol, has relatively simple preparation process, is easy to operate, and has relatively small using amount of formaldehyde; the prepared modified phenolic resin for foaming has low viscosity, low slag rate and high mechanical strength. The papermaking waste is adopted to replace phenol, so that the production raw material cost can be effectively reduced, the papermaking waste can be consumed, and the waste treatment pressure is relieved.

The invention adopts the following technical scheme to solve the technical problems:

the invention provides a preparation method of modified phenolic resin for foaming, which comprises the following steps:

(1) mixing and reacting papermaking waste and a weak oxidant, and adjusting the pH value to 7-12 to obtain modified papermaking waste;

(2) mixing and reacting the modified papermaking waste, phenol and formaldehyde to obtain a material A;

(3) under the condition that the pH value is 8-12, mixing and reacting the material A and formaldehyde, cooling, and adjusting the pH value to 6.5-7;

in the step (1), the mass ratio of the papermaking waste to the weak oxidant is 1: (0.06-0.1).

In the step (1), the weak oxidant is Fe which is conventionally considered by a person skilled in the art³⁺An oxidizing agent having an ion oxidizing ability as an upper limit and a standard electrode potential value of less than 0.77V. In the invention, the weak oxidant can be ammonium persulfate, sodium hypochlorite and benzene peroxideOne or more of formyl, cyclohexanone peroxide and tert-butyl peroxide, preferably ammonium persulfate or sodium hypochlorite.

In the step (1), the papermaking waste is papermaking waste which is conventionally generated in a papermaking process, such as one or more of black liquor, hydrolyzed lignin, sulfonate lignin and enzymatic hydrolyzed lignin.

The black liquor may be a waste liquor conventionally produced in pulping processes in the papermaking arts, for example, black liquor produced by the black liquor making process of chinese patent application 201610572635.8.

The method for preparing the hydrolyzed lignin can be a conventional method in the field, for example, the method for preparing the hydrolyzed lignin in the seventeenth volume, second chapter 2.2 of forest product chemistry.

The lignosulfonate may be a product conventionally regarded by those skilled in the art as being made by sulfonation of lignin, for example, lignosulfonate made by a method for preparing a lignosulfonate water-reducing agent from a soda pulping waste liquor in chinese patent application 201910834026.9.

The preparation method of the enzymatic hydrolysis lignin can be conventional in the field, such as influencing factors in the preparation process of the enzymatic hydrolysis lignin, paper-making science and technology, 1993(4): 29-31.

In the step (1), the solid content of the modified papermaking waste can be the conventional solid content of the substances in the field, and is preferably 10-80%. In the invention, the solid content of the modified papermaking waste generally refers to the mass percentage of dry materials of the modified papermaking waste after the solvent is removed in the modified papermaking waste. The person skilled in the art typically adjusts the solids content of the modified papermaking waste by adding water during the mixing reaction.

In the step (1), the mass ratio of the papermaking waste to the weak oxidizing agent is preferably 1: (0.08-0.1).

In the step (1), the temperature of the mixing reaction may be a temperature conventionally used in the art, preferably 65 to 95 ℃, and more preferably 65 to 75 ℃.

In the step (1), the mixing reaction time may be a time conventionally used in the art, and is preferably 20 to 60min, and more preferably 20 to 30 min.

In the step (1), the condition and method for adjusting the pH may be conventional conditions and methods in the field, and generally, the pH may be adjusted to 7 to 12 by using an alkaline pH adjusting agent, and preferably, the pH is adjusted to 8.5 by using an alkaline pH adjusting agent.

The alkaline pH regulator may be an alkaline pH regulator conventionally used in the art, and is preferably an aqueous solution of potassium hydroxide, and more preferably an aqueous solution of potassium hydroxide with a mass percentage of 32%. In the invention, the mass percentage is the mass percentage of the potassium hydroxide in the potassium hydroxide aqueous solution.

In a preferred embodiment, step (1) is performed by programmed heating and stepwise reaction, and specifically comprises the following steps: step a, mixing papermaking waste and a part of weak oxidant for reaction to prepare a material B; b, mixing the material B with the residual weak oxidant for reaction, and adjusting the pH value to 7-12 to prepare modified papermaking waste;

the weak oxidant in the step a and the weak oxidant in the step b are added dropwise; in the step a, the mixing reaction is carried out within 15-20 min, and the temperature is programmed to 65-70 ℃; in the step b, the mixing reaction is carried out within 15-20 min, the temperature is continuously programmed to 70-75 ℃ on the basis of the reaction temperature in the step a, and then the temperature is kept for 20-30 min; in the step a, the mass of the part of weak oxidizing agent accounts for 30-60% of the total mass of the weak oxidizing agent; in the step b, the percentage of the residual weak oxidizing agent in the total mass of the weak oxidizing agent is 40-70%.

In the step (2), the mass ratio of the phenol to the papermaking waste in the step (1) may be 1: (0.2 to 0.4), preferably 1: 0.3.

in the step (2), the mass ratio of the phenol to the formaldehyde may be 1: (0.7 to 1.5), preferably 1: (0.72 to 1.5), preferably 1: (1.08-1.5).

In the step (2), the time of the mixing reaction may be a time conventionally used in the art, and is preferably 10 to 60min, and more preferably 30 min.

In the step (2), the temperature of the mixing reaction may be a temperature that is conventional in the art, preferably 65 to 95 ℃, and more preferably 75 to 95 ℃.

In the step (2), the mass ratio of the phenol to the formaldehyde in the step (3) may be 1: (0.48 to 1), preferably 1: (0.72-1).

In the step (3), the time of the mixing reaction may be a time conventionally used in the art, and is preferably 30 to 90min, and more preferably 70 to 90 min.

In the step (3), the temperature of the mixing reaction may be a temperature that is conventional in the art, preferably 65 to 95 ℃, and more preferably 75 to 95 ℃.

In the step (3), the pH is preferably 8.5 to 9.5, for example, 9, during the mixing reaction.

In the step (3), the method for adjusting the pH value to 8-12 during the mixing reaction can be adjusted by adding an alkaline pH regulator which is conventionally used in the field.

The alkaline pH regulator may be one or more of those conventionally used in the art, preferably one or more of sodium hydroxide, potassium hydroxide, calcium oxide, magnesium oxide and zinc oxide, and more preferably an aqueous solution of potassium hydroxide, for example, an aqueous solution of potassium hydroxide with a mass percentage of 32%. In the invention, the mass percentage is the mass percentage of the potassium hydroxide in the potassium hydroxide aqueous solution.

In the step (3), the cooling condition and method may be the conditions and methods conventional in the art, preferably cooling to 50-70 ℃, more preferably cooling to 60-70 ℃.

In the step (3), the condition and method for adjusting the pH to 6.5-7 may be conditions and methods conventional in the operation in the field, and preferably, an acidic pH regulator is used for adjusting the pH of the system to 6.5-7.

The acidic pH regulator may be an acidic pH regulator conventionally used in the art, and is preferably one or more of hydrochloric acid, formic acid and acetic acid, and more preferably a 30% aqueous solution of formic acid.

The invention also provides a modified phenolic resin for foaming, which is prepared by the preparation method of the modified phenolic resin for foaming.

The solid content of the modified phenolic resin for foaming can be conventional in the art, and is preferably 70-90%, more preferably 71.3-71.8%, for example 71.5%.

The viscosity of the modified phenolic resin for foaming at 25 ℃ may be 5000 to 12000 mPaS, preferably 7350 to 9140 mPaS, for example 8000 mPaS.

The modified phenolic resin for foaming may have a free phenol and free aldehyde content of less than 1%.

The invention also provides an application of the modified phenolic resin for foaming as a raw material in preparing a foaming material.

The invention also provides a foaming material which is prepared by mixing and curing the modified phenolic resin for foaming, the curing agent, the surfactant and the foaming agent.

Among them, the curing agent may be one conventionally used in the art, and preferably oxalic acid.

The surfactant may be a surfactant conventionally used in the art, preferably tween-80.

The blowing agent may be a blowing agent conventionally used in the art, preferably n-pentane.

The mass ratio of the curing agent to the modified phenolic resin for foaming can be conventional in the field, and is preferably (4-7): 100, more preferably 5: 100.

the mass ratio of the surfactant to the modified phenolic resin for foaming can be conventional in the field, and is preferably (4-9): 100, more preferably 6: 100.

the mass ratio of the foaming agent to the modified phenolic resin for foaming can be conventional in the field, and is preferably (4-9): 100, more preferably 6: 100.

the curing temperature may be any temperature conventional to such operations in the art, preferably from 60 ℃ to 75 ℃.

The curing time can be the time conventional in the operation in the field, and is preferably 10-15 min.

On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows: the modified phenolic resin for foaming is prepared by taking papermaking waste as a raw material to replace part of phenol, so that the production cost can be effectively reduced; and the pressure of waste treatment in the papermaking field is relieved while the papermaking waste is consumed; the preparation method of the modified phenolic resin for foaming effectively improves the binding capacity among formaldehyde, phenol and papermaking waste, greatly reduces the content of free aldehyde and free phenol, has relatively simple preparation process, is easy to operate, and has relatively small using amount of formaldehyde; the prepared modified phenolic resin for foaming has low viscosity, low slag rate and high mechanical strength.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.