Flexible high-molecular glue for formaldehyde-free plate and preparation process of flexible high-molecular glue

Abstract

The invention relates to the technical field of artificial board adhesives, and particularly discloses flexible polymer glue for a formaldehyde-free board and a preparation process of the flexible polymer glue. The glue is prepared from the following raw materials in parts by mass: 20000 to 30000 parts of clean water, 1100 to 1300 parts of polyvinyl alcohol, 300 to 500 parts of vinyl acetate-ethylene copolymer emulsion and 0.5 to 2 parts of a compound bean product defoaming agent. The preparation process comprises the following steps: in a dissolving stage, heating to 90 DEG C at a speed of 1-2 DEG C / min to fully dissolve PVA; in the modification stage, the temperature is reduced to 60 DEG C, the VAE emulsion is added, and stirring is conducted for 30 minutes at the speed of 150-250 rpm; finally, cooling and filtering are conducted, formaldehyde release can be thoroughly eliminated, and the green building material standard is met; the technical problems that the processing performance of a traditional MDI adhesive J is cracked, the performance is damaged by an organic silicon defoaming agent, and foam is difficult to control are solved.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of artificial board adhesives, and in particular to a flexible polymer glue for formaldehyde-free boards and a preparation process thereof. Background Art

[0002] With growing environmental awareness and stricter indoor air quality standards, the use of formaldehyde-based adhesives (such as urea-formaldehyde and phenolic resins) in traditional wood-based panels has been gradually restricted due to the release of free formaldehyde, which poses a threat to human health and the environment. Therefore, the development of formaldehyde-free, environmentally friendly adhesives has become a key research direction in the wood-based panel industry.

[0003] Currently, formaldehyde-free adhesives primarily include soy protein glue, starch glue, polyurethane glue, and water-based polymer emulsions. Among these, polyvinyl alcohol (PVA) and vinyl acetate-ethylene copolymer emulsion (VAE) have garnered widespread attention in formaldehyde-free board manufacturing due to their excellent bonding properties and environmental friendliness. However, existing single-component adhesives often suffer from insufficient bond strength, poor water resistance, high costs, or poor process adaptability, limiting their large-scale application in wood-based composites like particleboard.

[0004] Furthermore, traditional adhesives are prone to foaming during production, affecting coating uniformity and board quality, necessitating the introduction of high-efficiency defoamers. While commonly used silicone defoamers are effective, they can affect the stability and bonding properties of the adhesive.

[0005] It should be noted that the above content belongs to the technical knowledge scope of technical personnel. Since the technical content in this field is vast and too complicated, the above content of this application does not necessarily constitute prior art. Summary of the Invention

[0006] 1. Technical problem to be solved by the invention: The present invention provides a flexible polymer glue for formaldehyde-free boards and a preparation process thereof, which are used to solve the technical problems existing in the above-mentioned background technology.

[0007] 2. Technical solution: To achieve the above object, the present invention provides a technical solution: a flexible polymer glue for formaldehyde-free board, comprising the following raw materials in parts by weight: Clean water: 20,000-30,000 parts Polyvinyl alcohol (PVA): 1100-1300 parts Vinyl acetate-ethylene copolymer emulsion (VAE emulsion): 300-500 parts Compound soy product defoaming agent: 0.5-2 parts.

[0008] Furthermore, the polyvinyl alcohol has a degree of alcoholysis of 88% to 99% and a viscosity of 15 to 50 mPa·s.

[0009] Furthermore, the solid content of the vinyl acetate-ethylene copolymer emulsion is 40% to 60%.

[0010] Furthermore, the compound soy product defoaming agent comprises a complex of soy protein hydrolyzate and natural oil, has a pH value of 6-8, and an active ingredient content of ≥30%.

[0011] And a preparation process of a flexible polymer glue for formaldehyde-free boards, comprising the following steps: Weigh the following raw materials by mass: 28400 parts of clean water, 1200 parts of polyvinyl alcohol, 400 parts of vinyl acetate-ethylene copolymer emulsion, and 1 part of compound soy product defoamer; Dissolution: Add clean water to the reactor, start stirring and add the compound soy product defoamer, then slowly add polyvinyl alcohol. After adding, keep warm for 30 minutes to allow the polyvinyl alcohol to fully soak, then heat to 90°C and keep warm for 1 hour; Modification: After the polyvinyl alcohol is completely dissolved, cool to 60°C, add vinyl acetate-ethylene copolymer emulsion, and stir at this temperature for 30 minutes to carry out modification; Filtration: Cool the reaction product to 40°C, stop stirring, and filter with an 80-mesh filter; Packaging: The filtered glue liquid will be packaged and stored after passing the inspection.

[0012] Furthermore, the heating rate during dissolution is 1-2°C / min, and the stirring speed is 200-400 rpm.

[0013] Furthermore, the stirring speed in the modification stage is 150-250 rpm, and the cooling rate is 0.5-1.5°C / min.

[0014] 3.Beneficial effects: Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: This invention's rational design completely eliminates free formaldehyde release through a formaldehyde-free formulation, fundamentally addressing the carcinogenic risks of traditional formaldehyde adhesives. Furthermore, the innovative introduction of a naturally derived defoamer (a soy protein hydrolyzate and oil complex) effectively suppresses foam and ensures coating uniformity while avoiding the detrimental effects of silicone defoamers on the film's cohesion. This significantly enhances bond strength and provides excellent water resistance, significantly extending the lifespan and environmental adaptability of the wood-based panel.

[0015] It should be noted that the structures not introduced in the present invention are the same as those in the prior art or can be implemented by using the prior art, and are not described in detail here because they do not involve the design points and improvement directions of the present invention. DETAILED DESCRIPTION

[0016] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0017] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," "fixed," "provided with," "provided on," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may refer to mechanical connection or electrical connection; they may refer to direct connection or indirect connection through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0018] It should be noted that the structures not introduced in the present invention do not involve the design points and improvement directions of the present invention, and can adopt existing technologies known to those skilled in the art.

[0019] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0020] A preparation process of flexible polymer glue for formaldehyde-free board, Example 1 Formula and process parameters: Clean water: 28,400 parts Polyvinyl alcohol (PVA): 1200 parts (alcoholysis degree 95%, viscosity 30 mPa·s) VAE emulsion: 400 parts (solid content 55%) Compound soy product defoamer: 1 part (pH=7, active ingredient 35%) Preparation process: Dissolution: Add clean water to the reactor, start stirring (300 rpm), add defoamer, slowly add PVA, and keep warm for 30 minutes to soak; increase the temperature to 90℃ at 1.5℃ / min and keep warm for 1 hour.

[0021] Modification: Cool to 60°C (rate 1°C / min), add VAE emulsion, and stir at 200 rpm for 30 minutes.

[0022] Filtration and packaging: Cool down to 40℃ (rate 1℃ / min), filter through 80 mesh, and package after passing inspection.

[0023] Example 2 Formula and process parameters: Clean water: 30,000 parts PVA: 1100 parts (alcoholysis degree 88%, viscosity 50 mPa·s) VAE emulsion: 500 parts (solid content 60%) Compound soy product defoamer: 0.5 parts (pH=6, active ingredient 30%) Preparation process: Dissolution: stirring speed 400 rpm, heating rate 2°C / min (other conditions are the same as Example 1).

[0024] Modification: stirring speed 250 rpm, cooling rate 0.5°C / min (other conditions are the same as Example 1).

[0025] Comparative Example 1 Recipe differences: The defoamer was replaced with an equal amount of silicone defoamer, and the rest of the formula and process were the same as in Example 1.

[0026]

[0027] No formaldehyde was detected in the above examples, but the use of silicone defoaming agent resulted in a 17% decrease in bonding strength (because the defoaming agent residue affected the continuity of film formation), and the foam control was poor (bubble height ≥5.0 mm). In addition, this product also had a good bonding height, proving the key role of the compound soy product defoaming agent in the system compatibility.

[0028] The above-mentioned embodiments only express a certain implementation method of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the attached claims.

Claims

1. A flexible polymer glue for formaldehyde-free boards, characterized by: The following raw materials are used in parts by weight composition: Clean water: 20,000-30,000 parts Polyvinyl alcohol (PVA): 1100-1300 parts Vinyl acetate-ethylene copolymer emulsion (VAE emulsion): 300-500 parts Compound soy product defoaming agent: 0.5-2 parts.

2. The flexible polymer glue for formaldehyde-free boards according to claim 1, characterized in that: The polyvinyl alcohol has a degree of alcoholysis of 88% to 99% and a viscosity of 15 to 50 mPa·s.

3. The flexible polymer glue for formaldehyde-free boards according to claim 1, characterized in that: The solid content of the vinyl acetate-ethylene copolymer emulsion is 40% to 60%.

4. The flexible polymer glue for formaldehyde-free boards according to claim 1, characterized in that: The compound soy product defoamer comprises a compound of soy protein hydrolyzate and natural oil, has a pH value of 6-8, and an active ingredient content of ≥30%.

5. A process for preparing a flexible polymer glue for formaldehyde-free boards, characterized by: The following steps are involved: Weigh the following raw materials by mass: 28400 parts of clean water, 1200 parts of polyvinyl alcohol, 400 parts of vinyl acetate-ethylene copolymer emulsion, and 1 part of compound soy product defoamer; Dissolution: Add clean water to the reactor, start stirring and add the compound soy product defoamer, then slowly add polyvinyl alcohol. After adding, keep warm for 30 minutes to allow the polyvinyl alcohol to fully soak, then heat to 90°C and keep warm for 1 hour; Modification: After the polyvinyl alcohol is completely dissolved, cool to 60°C, add vinyl acetate-ethylene copolymer emulsion, and stir at this temperature for 30 minutes to carry out modification; Filtration: Cool the reaction product to 40°C, stop stirring, and filter with an 80-mesh filter; Packaging: The filtered glue liquid will be packaged and stored after passing the inspection.

6. The flexible polymer glue for formaldehyde-free boards and the preparation process thereof according to claim 5, characterized in that: The heating rate during dissolution is 1-2°C / min and the stirring speed is 200-400 rpm.

7. The flexible polymer glue for formaldehyde-free boards and the preparation process thereof according to claim 1, characterized in that: The stirring speed in the modification stage is 150-250 rpm, and the cooling rate is 0.5-1.5°C / min.

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