Water-based two-component solid wood plate splicing glue main agent for delaying foaming reaction and preparation method of water-based two-component solid wood plate splicing glue main agent

Abstract

The invention relates to a water-based double-component solid wood plate splicing glue main agent capable of delaying foaming reaction and a preparation method thereof, the water-based double-component solid wood plate splicing glue main agent is formed by mixing polyvinyl acetate latex and zinc oxide slurry according to the mass ratio of 6: 4-4: 6, and the zinc oxide slurry is prepared from the following components in parts by mass: 41.4-44.8 parts of water, 5-8 parts of polyvinyl alcohol, 0.32-6 parts of zinc oxide powder, 44-49.68 parts of heavy calcium powder, 0.1-0.3 part of a defoaming agent and 0.1-0.3 part of a preservative. After the main agent and the curing agent are mixed, the foaming reaction rate of a system can be remarkably reduced, so that the problem of glue overflow after glue preparation can be reduced, and the glue can be mixed in a large scale at a time, so that the process level of actual glue use is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based two-component solid wood plywood glue, and specifically relates to a water-based two-component solid wood plywood glue main agent with delayed foaming reaction and a preparation method thereof. Technical Background

[0002] Water-based two-component solid wood plywood glue is a high-end water-based two-component adhesive in the field of board splicing glue. It is often used in various production and manufacturing fields that require high dry and wet strength of integrated materials, solid wood furniture, ship wooden decks, container floors, etc. Water-based two-component solid wood plywood glue contains two components: a water-based glue main agent and an isocyanate curing agent. The main agent and the curing agent can be used after being mixed evenly. With the help of the chemical cross-linking reaction between the higher molecular weight thermoplastic resin in the main agent and the isocyanate compound of the curing agent, the bonding interface can have good bonding strength and water resistance. The main agent of the water-based glue uses water as a solvent. When isocyanate reacts with the resin in the main agent of the water-based glue, the foaming reaction between the isocyanate and the water molecules in the main agent is inevitable. Moreover, due to the large number of water molecules and small molecular volume, coupled with the emulsification effect of water-based glue, the foaming reaction (producing CO2) between water molecules and curing agent-NCO groups in the actual use of water-based two-component solid wood plywood glue is usually quite intense, and the prepared glue will undergo a large volume expansion in a short period of time, and quickly produce glue overflow, causing waste and pollution. In order to avoid this problem, workers often choose to use a small amount of glue multiple times when dispensing, which is not conducive to the single large-scale dispensing of plywood glue at the factory end. Therefore, reducing or reducing the foaming reaction rate of water-based two-component solid wood plywood glue in actual applications has a certain promoting significance for improving the application process level of plywood glue in terminal factories.

[0003] At present, the industry's strategies for reducing the rapid foaming reaction during the actual use of water-based two-component panel glue are mainly: 1. Reduce the contact area between water molecules and curing agent molecules (such as using a water-based glue system with large particle size and weak emulsification ability). 2. Increase the number of active functional groups on the water-based resin molecular chain in the main agent of the panel glue, change the type of active functional groups, increase the probability of the active groups in the resin reacting with the -NCO groups, and reduce the probability of the foaming reaction between the -NCO groups and water molecules. 3. By adding a suitable defoamer, the CO2 gas generated by the system is discharged in time. This strategy gradually increases the viscosity of the system as the reaction proceeds, and the bubbles in the later stage are difficult to discharge, and the volume expansion of the glue is still relatively severe. Summary of the invention

[0004] The present invention provides a water-based two-component solid wood plywood glue main agent with a delayed foaming reaction and a preparation method thereof. After the water-based plywood glue main agent of the present invention is mixed with a curing agent, the foaming reaction rate of the system can be significantly reduced, thereby reducing the problem of glue overflow after glue preparation, and glue can be prepared in large quantities at a single time, thereby improving the process level of actual glue use.

[0005] The present invention is achieved through the following technical solutions:

[0006] A water-based two-component solid wood plywood glue main agent with delayed foaming reaction is prepared by mixing polyvinyl acetate latex and zinc oxide slurry in a mass ratio of 6:4 to 4:6, wherein the zinc oxide slurry is prepared from the following components in mass fraction ratio:

[0007] Water 41.4-44.8

[0008] Polyvinyl alcohol 5-8

[0009] Zinc oxide powder 0.32-6

[0010] Heavy calcium powder 44-49.68

[0011] Defoamer 0.1-0.3

[0012] Preservatives 0.1-0.3.

[0013] The polyvinyl acetate latex is a hydroxyl-containing polyvinyl acetate acrylic latex.

[0014] The defoamer is a mineral oil defoamer.

[0015] The preservative is an isothiazolinone preservative.

[0016] The heavy calcium powder is 800 mesh heavy calcium powder.

[0017] The zinc oxide slurry is prepared by the following method:

[0018] At room temperature, add water to the reactor, control the stirring rate to 140-170rpm, slowly add the mixed polyvinyl alcohol granules, zinc oxide powder and heavy calcium powder into the reactor, add defoaming agent at the same time, gradually heat up to 90-100°C, keep warm for 1-2h and then start to cool down; when the temperature reaches 35-45°C, add preservative, continue stirring for 5-10min to obtain the zinc oxide slurry.

[0019] The present invention selects polyvinyl acetate emulsion as a base latex, introduces zinc oxide slurry, and prepares a plywood glue main agent containing zinc oxide compounds. When the water-based plywood glue main agent is mixed with the isocyanate curing agent PMDI in a certain proportion, the foaming reaction rate of the system is significantly lower than that of the plywood glue main agent without the addition of zinc oxide slurry.

[0020] Advantages of the present invention: The present invention can greatly reduce the rate of colloid foaming and expansion during the curing reaction between the main agent of the panel glue and the curing agent through the introduction of zinc oxide slurry, which is helpful for the single large-scale preparation and application of the panel glue at the factory end, and improves the overall construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a graph showing the relationship between the foaming ratio of the colloid and time after the main glue with different zinc oxide contents in Examples 1-5 is combined with a curing agent.

[0022] Figure 2 This is a graph showing the relationship between the foaming ratio of the colloid and time after the main glue with different zinc oxide contents in Examples 8 and 9 is combined with a curing agent. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with specific implementation cases.

[0024] In order to reflect the key technical node of the use of zinc oxide slurry in this article to reduce the foaming reaction rate during the curing process of water-based plywood glue, when preparing the plywood glue main agent in Examples 1-7, the mass ratio of polyvinyl acetate latex to zinc oxide slurry was controlled to be 5:5, the total weight of zinc oxide and heavy calcium powder in the zinc oxide slurry was controlled to account for 50% of the total slurry, the content of zinc oxide in the plywood glue main agent was changed, and the foaming reaction behavior of the plywood glue main agent prepared in each example and the isocyanate curing agent PM200 after mixing in a mass ratio of 10:1.5 was observed, and the relationship between the foaming ratio and the foaming time of each example was recorded (see Appendix). Figure 1 ). In Example 8, the mass ratio of polyvinyl acetate latex to zinc oxide slurry is controlled to be 4:6, and in Example 9, the mass ratio of polyvinyl acetate latex to zinc oxide slurry is controlled to be 6:4. The proportion and preparation method of zinc oxide slurry in Examples 8 and 9 are consistent with the zinc oxide slurry in Example 5. Examples 8 and 9 are subjected to foaming experiments in the same manner as Examples 1-7, and the foaming test results of Examples 8 and 9 are plotted in the attached figure. Figure 2 The main agent formula composition of the water-based plywood glue of Examples 1-9 and related comparative examples is plotted in Table 1.

[0025] Table 1 The formula composition of the main agent of water-based panel glue in different embodiments

[0026]

[0027] The main agent of the board glue of the above-mentioned embodiments 1-5 and the control example was stirred and mixed with the isocyanate curing agent PM200 at a mass ratio of 10:1.5, and the foaming ratio of the embodiments 1-5 and the control example was tracked every 5 minutes to draw a foaming ratio-time relationship diagram, as shown in the attached figure. Figure 1 As shown. Figure 1 It can be seen that the foaming rate of each embodiment after the preparation of the glue does not foam in the first 5 minutes; after 5 minutes, the difference in the foaming rate gradually increases, and from Figure 1It was found that the colloid without zinc oxide in the main agent of the puzzle glue (control example) had a more obvious foaming ratio than that with zinc oxide (Examples 1-5), and with the increase of zinc oxide content in the main agent, the foaming ratio of the colloid decreased significantly and the time to start foaming was significantly delayed. 25 minutes after the main agent of the puzzle glue and the curing agent were mixed and prepared, the foaming ratio of the puzzle glue prepared by the main agent of the control example was as high as 110%, while the foaming ratio of the puzzle glue prepared by the main agent of the puzzle glue with 1.14% zinc oxide added (Example 5) was 0, that is, no foaming at all, and the latter did not foam at all within the entire test of 45 minutes. Figure 1 From the overall trend, it can be seen that the higher the zinc oxide content in the example, the lower the foaming ratio of the prepared puzzle glue in the same time and the more delayed the time of starting foaming, indicating that the delayed foaming reaction water-based two-component puzzle glue main agent and the preparation method thereof provided in this article are effective.

[0028] The zinc oxide slurry of Examples 1-5 was prepared by the following method:

[0029] At room temperature, water is added to the reactor, the stirring rate is controlled to 150 rpm, the mixed polyvinyl alcohol granules, zinc oxide powder and heavy calcium powder are slowly added to the reactor, and a defoaming agent is added at the same time. The temperature is gradually raised to 95°C, and the temperature is lowered after keeping warm for 1 hour; after the temperature drops to 40°C, a preservative is added, and stirring is continued for 7 minutes to obtain the zinc oxide slurry.

[0030] The zinc oxide slurry of Example 6 was prepared by the following method:

[0031] At room temperature, water is added to the reactor, the stirring rate is controlled to 140 rpm, the mixed polyvinyl alcohol granules, zinc oxide powder and heavy calcium powder are slowly added to the reactor, and a defoaming agent is added at the same time. The temperature is gradually raised to 90°C, and the temperature is lowered after keeping warm for 2 hours; after the temperature drops to 35°C, a preservative is added, and stirring is continued for 10 minutes to obtain the zinc oxide slurry.

[0032] The zinc oxide slurry of Example 7 was prepared by the following method:

[0033] At room temperature, water is added to the reactor, the stirring rate is controlled to be 170 rpm, the mixed polyvinyl alcohol granules, zinc oxide powder and heavy calcium powder are slowly added to the reactor, and a defoaming agent is added at the same time. The temperature is gradually raised to 100°C, and the temperature is lowered after keeping warm for 1 hour; after the temperature drops to 35-45°C, a preservative is added, and the zinc oxide slurry is obtained after continuing stirring for 5 minutes.

[0034] The relationship curves of the foaming ratio and time of Examples 6 and 7 are consistent with that of Example 5, that is, no foaming occurs within the entire 45 minutes of the test, indicating that when the zinc oxide content in the main agent of the water-based plywood glue exceeds 1.14%, no matter how the content of components such as polyvinyl alcohol, heavy calcium powder, defoaming agent, and preservative in the system changes, the system will still not foam. However, since the price of zinc oxide is more expensive than that of ordinary heavy calcium powder, considering the comprehensive formula cost advantage and performance requirements, it is recommended that the zinc oxide content accounts for 2%-3% of the total amount of the main agent of the water-based two-component solid wood plywood glue that delays the foaming reaction.

[0035] The ratio and preparation method of the zinc oxide slurry in Examples 8 and 9 are consistent with those in Example 5. The ratio of polyvinyl acetate latex: zinc oxide slurry in the main agent of the plywood glue is changed to 4:6 (Example 8) and 6:4 (Example 9), and the respective expansion ratio-foaming time curves are recorded (such as Figure 2 ).Depend on Figure 2 It can be seen that Example 8 does not foam at all within 45 minutes, which may be due to the fact that the zinc oxide content in the system is sufficiently high (1.37%), exceeding the 1.14% of Example 5; while Example 9 has a foaming curve with obvious changes within 45 minutes, which may be due to the fact that the zinc oxide content in the system is only 0.91%, which is less than 1.14% of Example 5; at the same time, by comparing Example 9 with Example 4, it is found that the zinc oxide content of Example 4 is lower than that of Example 9, but the foaming of Example 4 is slower than that of Example 9, which may be due to the fact that the polyvinyl acetate emulsion content in Example 9 is higher than that in Example 4, and the emulsification effect of the system is better than that of Example 4, so after mixing with the curing agent, Example 9 has a higher foaming ratio than Example 4 within the same time.

[0036] The polyvinyl acetate latex in the above embodiment is a hydroxyl-containing vinyl acetate latex (Sankeshu high-performance plywood glue SK-PJ948EP). The defoamer is a mineral oil defoamer (Deqian Defom W-086). The preservative is an isothiazolinone preservative (Guangdong Dimei Biological WAP601). The heavy calcium powder is 800 mesh heavy calcium powder (Jingfu JF800); zinc oxide powder (Aolong Zinc Industry, superior grade).

[0037] The present invention is not limited to the above embodiments, and all replacements and improvements made based on the principles of the present invention are within the protection scope of the present invention.

Claims

1. A water-based two-component solid wood plywood glue main agent with delayed foaming reaction, characterized in that: The zinc oxide slurry is prepared by mixing polyvinyl acetate latex and zinc oxide slurry in a mass ratio of 6:4 to 4:

6. The zinc oxide slurry is prepared by the following components in mass proportions: Water 41.4-44.8 Polyvinyl alcohol 5-8 Zinc oxide powder 0.32-6 Heavy calcium powder 44-49.68 Defoamer 0.1-0.3 Preservatives 0.1-0.

3.

2. The aqueous two-component solid wood plywood glue main agent with delayed foaming reaction according to claim 1, characterized in that: The polyvinyl acetate latex is a hydroxyl-containing polyvinyl acetate acrylic latex.

3. The aqueous two-component solid wood plywood glue main agent with delayed foaming reaction according to claim 1, characterized in that: The defoamer is a mineral oil defoamer.

4. The aqueous two-component solid wood plywood glue main agent with delayed foaming reaction according to claim 1, characterized in that: The preservative is an isothiazolinone preservative.

5. The aqueous two-component solid wood plywood glue main agent with delayed foaming reaction according to claim 1, characterized in that: The heavy calcium powder is 800 mesh heavy calcium powder.

6. The water-based two-component solid wood plywood glue main agent with delayed foaming reaction according to claim 1, Features: The zinc oxide slurry is prepared by the following method: At room temperature, add water to the reactor, control the stirring rate to 140-170rpm, slowly add the mixed polyvinyl alcohol granules, zinc oxide powder and heavy calcium powder into the reactor, add defoaming agent at the same time, gradually heat up to 90-100°C, keep warm for 1-2h and then start to cool down; when the temperature reaches 35-45°C, add preservative, continue stirring for 5-10min to obtain the zinc oxide slurry.

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