CN104530639B - Phenolaldehyde moulding compound of lignin modification and preparation method thereof - Google Patents

Abstract

A lignin-modified phenolic molding compound and a preparation method thereof, wherein the lignin-modified thermoplastic phenolic resin is uniformly blended with curing agents, fillers, release agents, pigments and other additives, and semi-cured on an open plastic refining machine, A flaky brittle product with good gloss is obtained, and after being crushed, it is passed through 200 mesh to obtain a molding compound. The bending strength of the lignin-based phenolic molding compound product is ≥70MPa, the notched impact strength is ≥1.3kJ/m ² , the unnotched impact strength is ≥4kJ/m ² , and the heat distortion temperature is ≥140°C.

Description

Lignin-modified phenolic molding compound and its preparation method

technical field

The invention relates to a lignin-modified phenolic molding compound and a preparation method thereof, in particular to a preparation method of lignin produced in the biofuel industry in a thermoplastic phenolic resin and a phenolic molding compound thereof.

Background technique

Phenolic molding compound is a material with excellent heat resistance and good cost performance, and its main component is phenolic resin. Phenolic resin is formed by polycondensation of phenolic compounds and aldehyde compounds under the action of a catalyst. Due to its low price, heat resistance, ablation resistance, flame retardancy, and less combustion smoke, it is widely used in adhesives, coatings, and molding compounds. , laminated plastics, foamed plastics, and ion exchange resins. The production and use of phenolic resin will consume a large amount of petrochemical products, and bring a certain degree of pollution to the environment, affecting the entire ecosystem. Today, the prices of phenol and formaldehyde, which are used in the production of phenolic resin as the main petrochemical products, continue to increase, resulting in a sharp decline in the profits of my country's phenolic resin-related industries, which seriously affects the development of the phenolic resin industry.

Lignin is the only non-petroleum resource that can provide renewable aryl compounds in nature, and it is the second most abundant natural polymer after cellulose in the plant kingdom. Lignin molecules have many different types of active groups, which have the advantages of being renewable, degradable, and non-toxic. Enzymatic Hydrolysis Lignin (EHL for short) is a new type of lignin extracted from the residue of fuel ethanol produced by fermentation of plant straw. At present, most of the enzymatic lignin is used for incineration, not only its components have not been effectively used, but also pollute the environment. my country now produces 670 million tons of corn stalks per year, and 300 kg of fuel ethanol residues can be obtained by fermenting 1 ton of corn stalks. Therefore, the efficient use of enzymatic lignin can not only make rational use of resources, but also replace petrochemical products and protect the environment. The lignin used in the present invention is derived from residues of fuel produced from agricultural waste such as corn cobs and corn stalks. Cheng Xiansu et al. used organic solvent extraction and inorganic chemical treatment to separate and extract enzymatic lignin from the residue of microbial enzymatic hydrolysis of corn stalks, and to prepare biomodified hot-melt phenolic resin. This method increased production costs.

In the research on the application of lignin in phenolic resins, the application in wood adhesives is mostly reported, and the application in thermoplastic phenolic resins is rarely reported. Matuana studied different types of lignin instead of phenolic resin; Peng and Khharade studied the mechanical behavior of lignin in phenolic resin, and used modern analytical methods to study the resin molecular structure obtained by the addition and polycondensation of lignin, phenol and formaldehyde; Wang Dizhen used The methylolation method studies the preparation of lignin thermoplastic phenolic resins. Due to the large molecular weight of lignin (compared with the molecular weight of phenol and thermoplastic phenolic resins), the reactivity of lignin is relatively low, and methylolation does not Increasing the number of active points only changes the active points on the benzene ring of lignin into hydroxymethyl groups. Some literature shows that the reactivity of lignin is only one-tenth of that of phenol, so in the above research, lignin is mainly used as a filler, rather than really reacting with phenol formaldehyde. This patent adopts phenolization method to liquefy and degrade biofuel lignin. Since the active functional groups of lignin from this source are well preserved, the degradation products contain more small molecular phenolic compounds, which can effectively realize the effect of lignin on lignin. Effective alternative to phenol.

Contents of the invention

The technical problem to be solved: the present invention provides a lignin-modified phenolic molding compound with green environmental protection, low cost and good comprehensive performance and its preparation method. The preparation method is simple and effectively utilizes the residue produced in the preparation process of biomass fuel. Promoted the development of the biofuel industry.

Technical solution: The preparation method of lignin-modified phenolic molding compound. The lignin is phenolized and degraded with phenol as the solvent under the acidic catalyst. After the degradation is completed, liquid formaldehyde is added and reacted at 80-100°C for 2-3 hours, and then Atmospheric pressure distillation removes moisture and phenol, obtains black brittle _lignin - _modified thermoplastic phenolic resin; _{Thermoplastic phenolic resin} +W _{t ordinary thermoplastic phenolic resin} )=20%-100% mass ratio mixed with curing agent, filler, mold release agent and pigment blending evenly, concrete composition is lignin phenolic resin+common phenolic resin 137 parts , 22 parts of curing agent, 125 parts of filler, 3 parts of magnesium oxide, 4.2 parts of slaked lime, 3.1 parts of stearic acid, 7.8 parts of Sanfei powder, 5 parts of water, 2.9 parts of ink black and 7.8 parts of talcum powder, and then in the open refining Semi-cured treatment on the plastic machine, low temperature roller 40-60℃, high temperature roller 140-180℃, roller distance 1.5-2.5mm, time 2-5min, to obtain flake brittle products, after crushing, pass through 200 meshes to obtain lignin Modified phenolic molding compound.

The lignin used is enzymatic lignin, hydrolytic lignin or alkali lignin produced in the biofuel industrial production.

The acid catalyst used is hydrochloric acid or oxalic acid.

The curing agent used is urotropine, paraformaldehyde or thermosetting resin.

The filler used is wood powder or bamboo powder.

The low temperature roller used is preferably 50°C; the high temperature roller is preferably 150°C; the roller distance is preferably 1.5-2mm, and the time is preferably 2-3min.

The lignin-modified thermoplastic phenolic resin and common phenolic resin used are W _{t lignin-modified thermoplastic phenolic resin} /(W _{t lignin-modified thermoplastic phenolic resin} +W _{t common thermoplastic phenolic resin} )=60%.

The lignin-modified phenolic molding compound prepared by the method has a bending strength of ≥70MPa, a notched impact strength of ≥1.3kJ/m ² , and an unnotched impact strength of ≥4kJ/m ² , heat distortion temperature ≥ 140 ℃.

Described lignin modified thermoplastic phenolic resin is prepared by the following method:

Mix phenol, acid catalyst and lignin, the mass ratio of lignin to phenol is 1: (1-4), adjust the pH value of the above reaction system to 1-3 by changing the amount of acid catalyst added, and then heat to 90°C -160°C, react for 1-3h, then add formaldehyde, the molar ratio of phenol to aldehyde is 1: (0.81-0.87), form a reaction system, adjust the reaction temperature to 90°C-200°C, react for 2-4h, first at normal pressure Then reduce the pressure, and distill off the moisture, residual phenol and formaldehyde in the system to obtain lignin-modified phenolic resin.

Beneficial effects: The increasing shortage of fossil energy has promoted the rapid development of biofuels, but at present the cost of biofuels is relatively high, and it is difficult to promote them. Research on high value-added applications of biofuel by-products is conducive to reducing the production costs of such enterprises and promoting The healthy development of biofuels in my country. In the invention, the product obtained by liquefying lignin phenol partially replaces phenol and formaldehyde as basic raw materials, reacts under the action of a catalyst, and obtains a phenolic resin product with low cost and low toxicity (reduced content of free phenol). Lignin phenol liquefaction products are mainly small molecules containing phenolic hydroxyl groups. Compared with lignin macromolecules, it has the characteristics of high reactivity, fast reaction speed and high production efficiency. Oxalic acid is a weak organic acid. Using oxalic acid as a catalyst to prepare high-ortho phenolic resin can increase the curing speed of the resin. For thermoplastic phenolic resins containing lignin, it is especially beneficial to the curing of products. Due to the increasing scarcity of petroleum resources, the research on lignin at home and abroad has become the focus, but there is no report on the application of biofuel lignin to molding materials. The present invention broadens the source of raw materials for preparing molding materials.

detailed description

The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, the modifications and substitutions made to the methods, steps or conditions of the present invention all belong to the scope of the present invention.

Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

The normal pressure mentioned in the present invention refers to one atmospheric pressure.

Example 1

Preparation of thermoplastic phenolic resin modified by enzymatic hydrolysis of lignin

Add 100 grams of phenol, enzymatic lignin (30% of phenol mass) and hydrochloric acid (5% of phenol mass) into the reactor, the reaction temperature is 95°C, and the reaction time is 2h, then add formaldehyde (phenol-formaldehyde molar ratio is 1:0.85 ), the reaction temperature is 90°C-110°C, the reaction time is 2h, the moisture and remaining phenol are removed under normal pressure and then under reduced pressure, and the enzymatic lignin modified phenolic resin is obtained. Ordinary thermoplastic phenolic resins are prepared in the same way.

Preparation of enzymatically hydrolyzed lignin-based phenolic molding compound

The above enzymatic lignin modified thermoplastic phenolic resin is blended with ordinary thermoplastic phenolic resin at 20%, 40%, 60%, 80%, 100%, and other additives such as curing agent, filler, mold release agent and pigment are blended. Mix evenly, the specific formula is 137 parts of lignin phenolic resin + common phenolic resin, 22 parts of urotropine, 125 parts of wood flour, 3 parts of magnesium oxide, 4.2 parts of slaked lime, 3.1 parts of stearic acid, 7.8 parts of sanfei powder, 5 parts of water, 2.9 parts of ink black and 7.8 parts of talcum powder are semi-cured on an open plastic refining machine with a low temperature roller of 40°C, a high temperature roller of 145°C, a roller distance of 1.5, and a time of 2.5 minutes. A flaky brittle product with good gloss is obtained, which is crushed and passed through 200 meshes for use.

Example 2

Preparation of Hydrolyzed Lignin Modified Thermoplastic Phenolic Resin

Add 100 grams of phenol, hydrolyzed lignin (40% of phenol mass) and oxalic acid (5% of phenol mass) into the reactor, the reaction temperature is 100°C, and the reaction time is 1.5h, then add formaldehyde (phenol-formaldehyde molar ratio is 1:0.85 ), the reaction temperature is 90°C-110°C, the reaction time is 2.5h, and the moisture and remaining phenol are removed under normal pressure and then under reduced pressure to obtain a hydrolyzed lignin-modified phenolic resin. Ordinary thermoplastic phenolic resins are prepared in the same way.

Preparation of hydrolyzed lignin-based phenolic molding compound

Blend the above-mentioned hydrolyzed lignin modified thermoplastic phenolic resin with ordinary thermoplastic phenolic resin at 20%, 40%, 60%, 80%, 100%, and blend with other additives such as curing agent, filler, mold release agent and pigment Uniform, the specific formula is 137 parts of lignin phenolic resin + common phenolic resin, 22 parts of paraformaldehyde, 125 parts of bamboo powder, 3 parts of magnesium oxide, 4.2 parts of slaked lime, 3.1 parts of stearic acid, 7.8 parts of sanfei powder, 5 parts of water 2.9 parts of ink black and 7.8 parts of talcum powder, semi-cured on the open plastic refining machine, low temperature roller 40-60 ℃; high temperature roller 14-180 ℃; roller distance 1.5-2.5mm, time 2-5min . A flaky brittle product with good gloss is obtained, which is crushed and passed through 200 meshes for use.

Example 3

Preparation of Alkali Lignin Modified Thermoplastic Phenolic Resin

Add 100 grams of phenol, alkali lignin (50% of phenol mass) and hydrochloric acid (6% of phenol mass) into the reactor, the reaction temperature is 98°C, the reaction time is 2.5h, then add formaldehyde (phenol-formaldehyde molar ratio is 1:0.85 ), the reaction temperature is 95°C-110°C, the reaction time is 4h, and the moisture and remaining phenol are removed under normal pressure and then under reduced pressure to obtain alkali lignin modified phenolic resin. Ordinary thermoplastic phenolic resins are prepared in the same way.

Preparation of Alkali Lignin Based Phenolic Molding Compound

Blend the above alkali lignin modified thermoplastic phenolic resin with ordinary thermoplastic phenolic resin at 20%, 40%, 60%, 80%, 100%, and blend with other additives such as curing agent, filler, mold release agent and pigment Uniform, the specific formula is 137 parts of lignin phenolic resin + common phenolic resin, 22 parts of paraformaldehyde, 125 parts of bamboo powder, 3 parts of magnesium oxide, 4.2 parts of slaked lime, 3.1 parts of stearic acid, 7.8 parts of sanfei powder, 5 parts of water 2.9 parts of ink black and 7.8 parts of talcum powder, semi-cured on the open plastic refining machine, low temperature roller 40-60 ℃; high temperature roller 14-180 ℃; roller distance 1.5-2.5mm, time 2-5min . A flaky brittle product with good gloss is obtained, which is crushed and passed through 200 meshes for use.

Example 4

Preparation of thermoplastic phenolic resin modified by enzymatic hydrolysis of lignin

Add 100 grams of phenol, enzymatic lignin (55% of phenol mass) and oxalic acid (6% of phenol mass) into the reactor, the reaction temperature is 105°C, and the reaction time is 3h, then add formaldehyde (phenol-formaldehyde molar ratio is 1:0.85 ), the reaction temperature is 100°C-110°C, the reaction time is 4h, the water and remaining phenol are removed under normal pressure and then under reduced pressure to obtain enzymatic lignin modified phenolic resin. Ordinary thermoplastic phenolic resins are prepared in the same way.

Preparation of enzymatically hydrolyzed lignin-based phenolic molding compound

The above enzymatic lignin modified thermoplastic phenolic resin is blended with ordinary thermoplastic phenolic resin at 20%, 40%, 60%, 80%, 100%, and other additives such as curing agent, filler, mold release agent and pigment are blended. Mix evenly, the specific formula is 137 parts of lignin phenolic resin + ordinary phenolic resin, 22 parts of thermosetting resin, 125 parts of wood flour, 3 parts of magnesium oxide, 4.2 parts of slaked lime, 3.1 parts of stearic acid, 7.8 parts of sanfei powder, 5 parts of water 2.9 parts of ink black and 7.8 parts of talcum powder, semi-cured on the open plastic refining machine, low temperature roller 40-60 ℃; high temperature roller 14-180 ℃; roller distance 1.5-2.5mm, time 2-5min . A flaky brittle product with good gloss is obtained, which is crushed and passed through 200 meshes for use.

Performance test results table of lignin-based phenolic molding compound

The resin conditions for preparing the splines in the table are as follows: lignin thermoplastic phenolic resin replaces 30% of phenol in the lignin thermoplastic phenolic resin, and the lignin thermoplastic phenolic resin accounts for 60% of the mass of the two resins.

Claims (2)

1. The preparation method of the lignin-modified phenolic molding compound is characterized in that 100 grams of phenol, enzymatic lignin accounting for 30% of the phenol mass and hydrochloric acid accounting for 5% of the phenol mass are added to the reactor, and the reaction temperature is 95 ℃, the reaction time is 2h, then add formaldehyde, the molar ratio of phenol to formaldehyde is 1:0.85, the reaction temperature is 90°C-110°C, the reaction time is 2h, the water and remaining phenol are removed under normal pressure and then under reduced pressure to obtain enzymatic lignin Modified phenolic resin; the preparation method of ordinary thermoplastic phenolic resin is the same; the above-mentioned enzymatic lignin modified thermoplastic phenolic resin is blended with ordinary thermoplastic phenolic resin at 60%, and other additives such as curing agent, filler, mold release agent and pigment Blend evenly, the specific formula is lignin phenolic resin + common phenolic resin 137 parts, urotropine 22 parts, wood flour 125 parts, magnesium oxide 3 parts, slaked lime 4.2 parts, stearic acid 3.1 parts, Sanfei powder 7.8 parts , 5 parts of water, 2.9 parts of ink black and 7.8 parts of talcum powder, half-cured on the open plastic refining machine, low temperature roller 40 ℃, high temperature roller 145 ℃, roller distance 1.5, time 2.5min, obtained a very good Glossy flaky brittle product, pass through 200 mesh after crushing for use. 2. The lignin-modified phenolic molding compound prepared by the method of claim 1, characterized in that the lignin-modified phenolic molding compound has a bending strength of 85MPa, a notched impact strength of 1.4kJ/ ^m2 , and no notched impact The strength is 6.2kJ/m ² , and the heat distortion temperature is 175°C.