CN103756609A - Plywood glue and preparation method thereof - Google Patents

Abstract

The invention relates to plywood glue and a preparation method thereof. According to the plywood glue, urea is added into formaldehyde containing polyvinyl alcohol by specific ratio and program so as to guarantee the environmental protection property of the glue; the process is simple and reasonable and the production cost is low; gelling is not caused in a production process and the glue is not sprayed; the production is safe and stable and the storage period is long.

Description

A kind of glued board glue and preparation method thereof

Technical field

The invention belongs to new material technology field, relate to a kind of glued board glue and production method thereof.

Background technology

For meeting the ever-increasing demand of timber-work, artificial fast growing wood and small diameter grade assortment will become the main raw material of wood processing industry.Therefore, making full use of felling residuum, industrial wood waste and inferior timber development wood-based plate and artificial splicing goods, is one of effective measure that solve timber imbalance between supply and demand, and tackiness agent plays very important effect therein.

At present in the world, according to burst size of methanal grade, be divided into E2, E1, tri-ranks of E0, be E2≤30mg/100g, E1≤9mg/100g, E0≤3mg/100g, E0 level refers to that in every 100g sample, the amount containing formaldehyde is less than or equal to 3mg, generally to take boring method to measure, only have in the world at present Finland and Japan to carry out similar E0 standard, the family product that meets this standard is international top environmentfriendly products.The production of E0 level high standard sheet material, requires all very high to the technology and equipment of producer.At present, most domestic medium-sized and small enterprises all also do not possess such throughput.

Summary of the invention

In order to overcome the above-mentioned shortcoming of prior art, the invention provides a kind of technique advantages of simple, cost of manufacture is cheap, can improve the production method of the environmental-protecting performance of wood-based panel product and the environment friendly aldehyde-free glued board glue of quality product.

The present invention realizes by following technology:

A production method for glued board glue, is characterized in that being made by following process steps:

(1) in molar ratio, polyvinyl alcohol is added in 100-160 formaldehyde doubly, react 10 minutes, and stirring adds alkali, tune pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5-5.5, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6-6.5, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.1-4.3, add the trimeric cyanamide doubly of urea amount 2-3 in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.0-8.2;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 6.6-7, put glue, obtain.

The present invention adds according to the proportioning gradation of urea, guaranteed the feature of environmental protection of glue, technique advantages of simple, cost of manufacture is cheap, in production process, can not cause gel, more can not spray cans, production safety is stable, shelf lives is more than 90 days, can deposit in the dog days of summer and the dead of winter, use, transport, this glue is zero through national environmental protection product quality supervision and inspection Spot detection free formaldehyde, adopt the burst size of methanal E0≤3mg/100g of the wood-based plate that environment-friendly type E0 level glue product of the present invention produces, improved environmental-protecting performance and the quality product of wood-based panel product.

Embodiment

Embodiment 1

(1) in molar ratio, polyvinyl alcohol is added in the formaldehyde of 100 times, react 10 minutes, and stir and add alkali, adjust pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.1, add the trimeric cyanamide of 2 times of urea amounts in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.0;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 6.6, put glue, obtain.

Embodiment 2

(1) in molar ratio, polyvinyl alcohol is added in the formaldehyde of 160 times, react 10 minutes, and stir and add alkali, adjust pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5.5, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6.5, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.3, add the trimeric cyanamide of 3 times of urea amounts in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.2;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 7, put glue, obtain.

Embodiment 3

(1) in molar ratio, polyvinyl alcohol is added in the formaldehyde of 120 times, react 10 minutes, and stir and add alkali, adjust pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5.3, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6.3, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.3, add the trimeric cyanamide of 2.5 times of urea amounts in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.1;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 6.8, put glue, obtain.

The binder performance that the present invention makes is as follows:

1. viscosity

Use NDJ-9s Digital Viscometer, by GB/T 2794-1995, measure.

2. stability

Mechanical stability: with 800 type centrifuge separators, under 3000r/min, rotate continuously 15 minutes, bureaucratic airs has or not layering; Room temperature stability: room temperature lower seal is standing, and routine observation has or not layering.

3. solid content

With reference to GB/T 2793-1995, measure

4. the cohesiveness of sizing agent

Wood specimen size 12cm*6cm*1.5cm, bond length 12cm, press curing 5d.Style is soaked respectively in 70 ℃ of water, 10% sulfuric acid and 10% sodium hydroxide solution, test water tolerance, erosion resistance.

5. surface drying time and doing solid work the time

Get the sizing agent of appropriate preparation, be applied on the glass dish after cleaning, test surface drying time and do solid work the time.

The results are shown in Table 1

Claims (2)

1. a production method for glued board glue, is characterized in that being made by following process steps:

(1) in molar ratio, polyvinyl alcohol is added in 100-160 formaldehyde doubly, react 10 minutes, and stirring adds alkali, tune pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5-5.5, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6-6.5, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.1-4.3, add the trimeric cyanamide doubly of urea amount 2-3 in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.0-8.2;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 6.6-7, put glue, obtain.

2. the production method of a kind of glued board glue according to claim 1, is characterized in that being made by following process steps:

(1) in molar ratio, polyvinyl alcohol is added in the formaldehyde of 120 times, react 10 minutes, and stir and add alkali, adjust pH=10.5;

(2) urea is added in the mixture of step 1 gained, the mol ratio that adds the amount of urea to press on formaldehyde is 1:5.3, is warmed up to 70 ℃, keeps 1h, with HCl, regulates pH to 6.3, is cooled to 40 ℃;

(3) regulate again pH to 5, after 30 minutes, be adjusted to 4.3, add the trimeric cyanamide of 2.5 times of urea amounts in step 2, then add the urea of step 2 moderate, stir and be warming up to 80 ℃, until soltion viscosity while reaching 5000mPas, regulates pH to 8.1;

(4) by gained solution intensification vacuum hydro-extraction, then be cooled to 35 ℃, after adjusting pH to 6.8, put glue, obtain.