A non-formaldehyde plant gum and a method for preparing the same

Abstract

The application discloses a kind of formaldehyde-free plant glue, the formaldehyde-free plant glue is two-component foaming glue, the two-component foaming glue includes colloid and curing component, the foaming rate of the formaldehyde-free plant glue is 40-80%.The formaldehyde-free plant glue prepared in the application can extend the operable time, the development time is long before hot pressing, and the curing time is short after hot pressing.The weight ratio of water and isocyanate in the raw material prepared in the application is 0.1996:25, which can balance the gel reaction and foaming reaction of the foaming glue, so that the foaming is uniform without affecting the strength of the board.The cell of the foaming glue after foaming is uniform small pore, which improves the glue layer strength and improves the bonding strength.In the bonding of sandwich structure of board, the bonding strength is large, and the colloid is not easy to be damaged during peeling.

Description

Technical Field

[0001] The present invention relates to the field of C09J adhesives, and in particular to formaldehyde-free plant glue and a preparation method thereof. Background Art

[0002] Formaldehyde-free plant-based glue is a material that foams after a colloid is heated to a certain temperature. The substances in the colloid enter the foam and then quickly set and solidify. Foamed glue has excellent heat insulation, sound absorption, and shock absorption effects. Therefore, it is widely used in the manufacture of sound insulation, heat insulation, thermal insulation, and cold insulation materials, and is widely used in the furniture and automotive industries. Existing foamed materials have a short open time and workers have short operating time, which makes the processing technology of foamed glue more difficult and limits the development of foamed glue. Therefore, it is crucial to develop a foamed glue with a long open time and a short curing time, which can reduce the difficulty of foamed glue processing without affecting the preparation efficiency.

[0003] Chinese invention patent CN101735762A discloses a polyurethane two-component foam adhesive for laminating interior and exterior walls and its production method. 100 parts of glue A can be laminated to 50-110 parts of glue B without affecting their bonding strength. It can be operated at low temperatures between -3°C and -5°C and can only be bonded after being stirred evenly. In the case of slightly uneven walls, micro-foaming can help fill the gap between the wall and the board, preventing rainwater from entering the interior to form an isolation layer, which can achieve better thermal insulation effects. However, plasticizers need to be added, and the environmental protection effect is not good. Chinese invention patent CN106634784A discloses a two-component polyurethane foam adhesive with good compatibility between the two components. The foam adhesive has good bonding properties, water resistance, and durability with the substrate. The foam adhesive does not use solvents, is pollution-free, and is green and environmentally friendly, but it will affect the bonding strength between the adhesive and the metal plate. Summary of the Invention

[0004] In order to develop a foaming glue with a long open time and a short curing time, while reducing the difficulty of foaming glue processing without affecting the preparation efficiency, the first aspect of the present invention provides a formaldehyde-free plant glue, which is a two-component foaming glue. The two-component foaming glue includes a colloid and a curing component, and the foaming rate of the formaldehyde-free plant glue is 40-80%.

[0005] As a preferred embodiment, the weight ratio of the colloid to the curing component is 100:(20-30).

[0006] As a preferred embodiment, the weight ratio of the colloid to the curing component is 100:25.

[0007] As a preferred embodiment, the curing component is isocyanate.

[0008] As a preferred embodiment, the raw materials for preparing the colloid include, by weight: 5-15 parts of polyol polymer, 15-35 parts of hydroxyl-containing compound, 55-75 parts of calcium filler, 0.1-0.3 parts of catalyst, 0.1-0.5 parts of foam modifier, and 0.1-0.3 parts of water.

[0009] As a preferred embodiment, the raw materials for preparing the colloid include, by weight: 8-13 parts of polyol polymer, 20-30 parts of hydroxyl-containing compound, 60-70 parts of calcium filler, 0.1-0.3 parts of catalyst, 0.3-0.5 parts of foam modifier, and 0.1-0.3 parts of water.

[0010] As a preferred embodiment, the raw materials for preparing the colloid include, by weight: 10 parts of polyol polymer, 25.2 parts of hydroxyl-containing compound, 64.2 parts of calcium filler, 0.2 parts of catalyst, 0.4 parts of foam modifier, and 0.2 parts of water.

[0011] As a preferred embodiment, the weight ratio of water to solidifying component is (0.15-0.25):25; preferably, the weight ratio of water to solidifying component is (0.18-0.2):25; further preferably, the weight ratio of water to solidifying component is 0.1996:25.

[0012] During experiments, the inventors discovered that a water-to-isocyanate ratio of 0.1996:25 in the foaming gel balances the gelling and foaming reactions, ensuring uniform foaming without compromising the strength of the board. The inventors speculate that this is due to the reaction of hydroxyl groups in the water with the isocyanate to produce carbon dioxide, which creates pores. However, when the water and isocyanate ratios are below the optimal range, the foaming rate is too low to meet foaming requirements. When the water and isocyanate ratios are above the optimal range, the foaming rate is too high, affecting the gel strength of the foaming gel. This, in turn, impacts the board's strength upon contact with the steel and glass-magnesium boards.

[0013] As a preferred embodiment, the hydroxyl value of the polyol polymer is 250-300 mgKOH / g, and the viscosity of the polyol polymer at 25° C. is 40-140 mPa·s.

[0014] As a preferred embodiment, the hydroxyl value of the polyol polymer is 270-290 mgKOH / g, and more preferably, the hydroxyl value of the polyol polymer is 280 mgKOH / g.

[0015] As a preferred embodiment, the polyol polymer is a polyether polyol.

[0016] As a preferred embodiment, the hydroxyl-containing compound includes natural oils and / or polyols, and the hydroxyl value of the natural oils and fats is 150-200 mgKOH / g.

[0017] As a preferred embodiment, the natural oil is castor oil.

[0018] As a preferred embodiment, the polyol is at least one selected from glycerol, polyethylene glycol, polypropylene glycol, sorbitol, mannitol, and xylitol.

[0019] As a preferred embodiment, the polyol is glycerol.

[0020] As a preferred embodiment, the average particle size of the calcium filler is ≤44 μm, and the calcium filler is selected from at least one of calcium carbonate, calcium oxide, active calcium, and calcium sulfate.

[0021] As a preferred embodiment, the calcium filler includes calcium carbonate and active calcium, the particle size of the calcium carbonate is 500-1000 mesh, and the particle size of the active calcium is 2-5 μm.

[0022] As a preferred embodiment, the particle size of the calcium carbonate is 800 mesh, and the particle size of the active calcium is 2.76-3.65 μm.

[0023] As a preferred embodiment, the weight ratio of calcium carbonate to active calcium is (60-70): (0.1-0.3).

[0024] As a preferred embodiment, the weight ratio of calcium carbonate to active calcium is 64:0.2.

[0025] As a preferred embodiment, the catalyst is selected from at least one of a tin catalyst, an aliphatic amine catalyst, a thermosensitive catalyst, an alcohol catalyst, and an aromatic amine catalyst.

[0026] As a preferred embodiment, the catalyst is a thermosensitive catalyst, and more preferably, the catalyst is Evonik SA1 thermosensitive catalyst.

[0027] During the experiment, the inventors found that the formaldehyde-free plant glue prepared by using a heat-sensitive catalyst can extend the operating time. Before hot pressing, the development time is long, and the curing time after hot pressing is short. It is speculated that the possible reason is: it is necessary to control the foaming time of the formaldehyde-free plant glue. If the foaming is too fast, it will affect the open time, the workers will have short construction time, and it will be difficult to operate. If the foaming is slow, it will affect the pressure relief time and reduce production efficiency. The inventors used a heat-sensitive catalyst. In the early stage of the reaction, the reaction temperature is low and the reaction speed is slow, so there is a certain open time for workers to operate. As the reaction proceeds, after hot pressing, the temperature rises, the reaction speed increases, and the foam glue can accelerate the curing, thereby shortening the pressure relief time and improving production efficiency.

[0028] As a preferred embodiment, the foam modifier includes a foam leveling agent and a defoaming agent, and the weight ratio of the foam leveling agent to the defoaming agent is (0.1-0.3): (0.1-0.3).

[0029] As a preferred embodiment, the weight ratio of the foam leveling agent to the defoaming agent is (0.15-0.25): (0.15-0.25).

[0030] As a preferred embodiment, the weight ratio of the foam leveling agent to the defoaming agent is 0.2:0.2.

[0031] During their experiments, the inventors discovered that the cells produced by hot-pressing foaming are uneven in size. Especially during rapid foaming and curing after hot pressing, the cells fuse and enlarge, affecting the uniformity of the adhesive layer and, in turn, the bond strength after the panels are bonded. By introducing a silicone foam leveler, using a weight ratio of 0.2:0.2 between the foam leveler and defoamer, they were able to reduce cell fusion and maintain uniform foaming.

[0032] A second aspect of the present invention provides a method for preparing formaldehyde-free plant gum, comprising the following steps:

[0033] S1: uniformly mixing the polyol polymer and the hydroxyl-containing compound;

[0034] Add calcium filler to S2 and stir at a speed of 1000-2000r / min to disperse evenly;

[0035] S3 adds catalyst, foam modifier and water to disperse evenly, cools to below 50°C, and discharges to obtain colloid;

[0036] S4 mixes the colloid and the curing component to obtain formaldehyde-free plant glue.

[0037] As a preferred embodiment, the high-speed dispersion in step S2 generates heat, and the colloid temperature is 70-80°C.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The formaldehyde-free plant glue of the present invention adopts a thermosensitive catalyst, and the formaldehyde-free plant glue prepared can extend the operating time, the development time before hot pressing is long, and the curing time after hot pressing is short.

[0040] (2) The formaldehyde-free plant glue of the present invention is prepared by using water and isocyanate in a weight ratio of 0.1996:25 in the raw materials, which can balance the gel reaction and foaming reaction of the foam glue, making the foaming uniform without affecting the strength of the board.

[0041] (3) The formaldehyde-free plant glue of the present invention adopts an organosilicon foaming agent, and the weight ratio of the foaming agent to the defoaming agent is 0.2:0.2, which can make the foaming cells of the foaming glue uniform small pores, increase the strength of the glue layer, and improve the bonding strength.

[0042] (4) The foaming rate of the foamed adhesive prepared by the formaldehyde-free plant glue of the present invention is 40-80%, and it is used for bonding a five-layer sandwich structure of color steel plate, glass magnesium plate, rock wool, glass magnesium plate, and color steel plate.

[0043] (5) The formaldehyde-free plant glue of the present invention has high bonding strength in the bonding of board sandwich structures, and the colloid is not easily destroyed during peeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The closure of the cells in the cross section of the foamed body of the formaldehyde-free plant gum prepared in Example 1 after foaming;

[0045] Figure 2 The closure of the cells in the cross section of the foamed body after foaming is shown for the formaldehyde-free plant gum prepared in Comparative Example 7.

[0046] Figure 3 The formaldehyde-free plant glue prepared in Example 1 is used to bond the color steel plate and the glass magnesium plate with glue. The damage of the glass magnesium plate after being torn by hand is shown.

[0047] Figure 4 The formaldehyde-free plant glue prepared in Example 2 is used to bond the color steel plate and the glass magnesium plate with glue. The damage of the glass magnesium plate after being torn by hand is shown.

[0048] Figure 5 The formaldehyde-free plant glue prepared in Example 3 is used to bond the color steel plate and the glass magnesium plate with glue. The damage of the glass magnesium plate after being torn by hand is shown.

[0049] Figure 6 The formaldehyde-free plant glue prepared in Comparative Example 6 is used to bond the color steel plate and the glass magnesium plate with glue. The damage of the glass magnesium plate after hand-tearing is shown.

[0050] Figure 7The formaldehyde-free plant glue prepared in Comparative Example 8, the color steel plate and the glass magnesium plate are bonded with glue, and the material damage of the glass magnesium plate after being torn by hand. DETAILED DESCRIPTION

[0051] Example 1

[0052] Disclosed is an aldehyde-free plant glue, which is a two-component foaming glue. The two-component foaming glue comprises a colloid and a curing component, and the weight ratio of the colloid to the curing component is 100:25.

[0053] The curing component is polymeric isocyanate MDI, purchased from Wanhua Chemical with the brand name PM200.

[0054] The raw materials for preparing the colloid include, by weight, 10 parts of polyol polymer, 25.2 parts of hydroxyl-containing compound, 64.2 parts of calcium filler, 0.2 parts of catalyst, 0.4 parts of foam modifier, and 0.2 parts of water.

[0055] The hydroxyl value of the polyol polymer is 280 mgKOH / g, the viscosity of the polyol polymer at 25° C. is 40-140 mPa·s, and the polyol polymer is a polyether polyol purchased from Wanhua Rongwei with the brand name WANOL C2004.

[0056] The hydroxyl-containing compound includes natural oil or polyol in a weight ratio of 25:0.2. The hydroxyl value of the natural oil is 150-200 mgKOH / g. The natural oil is castor oil purchased from Adani, a first-grade oil. The polyol is glycerol.

[0057] The calcium filler includes calcium carbonate and active calcium in a weight ratio of 64:0.2; the particle size of the calcium carbonate is 800 mesh, and the particle size of the active calcium is 2.76-3.65 μm. The active calcium is purchased from Zebang Chemical with the brand name ZB-777.

[0058] The catalyst is a thermosensitive catalyst purchased from Evonik SA1 thermosensitive catalyst.

[0059] The foam modifier includes a foam leveler and a defoamer in a weight ratio of 0.2:0.2. The foam leveler was purchased from Maihao with the brand name Y-16612, and the defoamer was purchased from Sixin Technology with the brand name SX08.

[0060] A method for preparing formaldehyde-free plant gum comprises the following steps:

[0061] S1: uniformly mixing the polyol polymer and the hydroxyl-containing compound;

[0062] Add calcium filler to S2 and stir at a speed of 1500r / min to disperse evenly;

[0063] S3 adds catalyst, foam modifier and water to disperse evenly, cools to below 50°C, and discharges to obtain colloid;

[0064] S4 mixes the colloid and the curing component to obtain formaldehyde-free plant glue.

[0065] Example 2

[0066] Disclosed is an aldehyde-free plant glue, which is a two-component foaming glue. The two-component foaming glue comprises a colloid and a curing component, and the weight ratio of the colloid to the curing component is 100:25.

[0067] The raw materials for preparing the colloid include, by weight, 5 parts of polyol polymer, 35 parts of hydroxyl-containing compound, 75 parts of calcium filler, 0.2 parts of catalyst, 0.4 parts of foam modifier, and 0.2 parts of water. The weight ratio of water to curing component is 0.1727:0.2.

[0068] The rest of the specific implementation is the same as that of Example 1.

[0069] Example 3

[0070] Disclosed is an aldehyde-free plant glue, which is a two-component foaming glue. The two-component foaming glue comprises a colloid and a curing component, and the weight ratio of the colloid to the curing component is 100:25.

[0071] The raw materials for preparing the colloid include, by weight, 15 parts of a polyol polymer, 15 parts of a hydroxyl-containing compound, 55 parts of a calcium filler, 0.2 parts of a catalyst, 0.4 parts of a foam modifier, and 0.2 parts of water, with a weight ratio of water to curing component of 0.2331:0.2.

[0072] The rest of the specific implementation is the same as that of Example 1.

[0073] Comparative Example 1

[0074] A formaldehyde-free plant gum and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the catalyst is dibutyltin dilaurate.

[0075] Comparative Example 2

[0076] A formaldehyde-free plant gum and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the catalyst is triethylenediamine.

[0077] Comparative Example 3

[0078] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25.2 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.1 part of a catalyst, 0.4 part of a foam modifier, and 0.2 part of water.

[0079] Comparative Example 4

[0080] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25.2 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.4 parts of a catalyst, 0.4 parts of a foam modifier, and 0.2 parts of water.

[0081] Comparative Example 5

[0082] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25.2 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.2 parts of a catalyst, 0.4 parts of a foam modifier, and 0.1 parts of water.

[0083] Comparative Example 6

[0084] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25.2 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.2 parts of a catalyst, 0.4 parts of a foam modifier, and 0.4 parts of water.

[0085] Comparative Example 7

[0086] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25.2 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.2 parts of a catalyst, 0.2 parts of a foam modifier, and 0.2 parts of water.

[0087] The foam modifier is a defoamer purchased from Sixin Technology, with the brand name SX08 defoamer.

[0088] Comparative Example 8

[0089] A formaldehyde-free plant glue and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the raw materials for preparing the colloid include, by weight, 10 parts of a polyol polymer, 25 parts of a hydroxyl-containing compound, 64.2 parts of a calcium filler, 0.2 parts of a catalyst, 0.4 parts of a foam modifier, and 0.2 parts of water.

[0090] The hydroxyl-containing compound is a natural oil, and the natural oil is castor oil, which has a hydroxyl value of 150-200 mgKOH / g and is purchased from Adani, a first-grade oil.

[0091] Performance Testing

[0092] After the colloid and curing component are mixed evenly in a weight ratio of 100:25, they are coated on the color steel plate with a coating thickness of 250g / m 2 .

[0093] 1. Open time: After coating, start timing until the colloid starts to foam, then end timing.

[0094] 2. Foaming rate: Foaming rate = [(volume of final foam - volume before foaming) / volume before foaming] × 100%

[0095] 3. Closed-cell ratio of foamed body: Cut the foamed colloid to see the closed-cell situation of the cross section. The closed-cell situation of Example 1 and Comparative Example 7 is shown in Figure 2. Figure 1 , Figure 2 .

[0096] 4. Bonding strength: The color steel plate and the glass magnesium plate were bonded by foam glue, and then torn by hand. The damage of the glass magnesium plate after tearing was observed. Figure 3-Figure 5 , Figure 6 , Figure 7 .

[0097] The test results of open time and foaming rate are shown in Table 1.

[0098] Table 1

[0099]

[0100] When the formaldehyde-free plant glue is hot-pressed at 60° C. and pressure can be released within 6 minutes, the longer the open time, the better. The technical effect of Example 1 is significantly better than that of Comparative Examples 1, 2, 3, and 4.

[0101] pass Figure 1 , Figure 2 Compared with the photos, the bubbles in Example 1 are uniform and small; the bubbles in Comparative Example 7 are larger and the uniformity is not high.

[0102] pass Figure 3-Figure 5 , Figure 6 , Figure 7 Comparing the photos, after the hot-pressed foaming agents of Examples 1-3 were torn by hand, the glass magnesium board was completely destroyed, but the colloid was not damaged; after the hot-pressed foaming agent of Comparative Example 6 was torn by hand, the glass magnesium board was slightly damaged, but the colloid was damaged; after the hot-pressed foaming agent of Comparative Example 8 was torn by hand, the glass magnesium board was obviously damaged, and the colloid was damaged.

Claims

1. A formaldehyde-free plant gum, characterized in that: The formaldehyde-free plant glue is a two-component foaming glue, which includes a colloid and a curing component. The foaming rate of the formaldehyde-free plant glue is 40-80%; The raw materials for preparing the colloid include, by weight, 5-15 parts of a polyol polymer, 15-35 parts of a hydroxyl compound, 55-75 parts of a calcium filler, 0.1-0.3 parts of a catalyst, 0.1-0.5 parts of a foam modifier, and 0.1-0.3 parts of water; the weight ratio of water to curing component is (0.15-0.25):25; The calcium filler includes calcium carbonate and active calcium, the particle size of the calcium carbonate is 500-1000 mesh, and the particle size of the active calcium is 2-5 μm; The foam modifier includes a foam leveling agent and a defoaming agent, and the weight ratio of the foam leveling agent to the defoaming agent is (0.1-0.3): (0.1-0.3); The hydroxyl-containing compound comprises natural oil and polyol, wherein the hydroxyl value of the natural oil is 150-200 mgKOH / g; The catalyst is a heat-sensitive catalyst; The curing component is isocyanate.

2. The formaldehyde-free plant glue according to claim 1, characterized in that The hydroxyl value of the polyol polymer is 250-300 mgKOH / g, and the viscosity of the polyol polymer at 25° C. is 40-140 mPa·s.

3. The formaldehyde-free plant glue according to claim 1, characterized in that The polyol is selected from at least one of glycerol, polyethylene glycol, polypropylene glycol, sorbitol, mannitol and xylitol.

4. A method for preparing the formaldehyde-free plant gum according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: uniformly mixing the polyol polymer and the hydroxyl-containing compound; Add calcium filler to S2 and stir at a speed of 1000-2000r / min to disperse evenly; S3 adds catalyst, foam modifier and water to disperse evenly, cools to below 50°C, and discharges to obtain colloid; S4 mixes the colloid and the curing component to obtain formaldehyde-free plant glue.

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