Flame-retardant glue for water-based backlit film and preparation method of flame-retardant glue

Abstract

The invention discloses flame-retardant glue for a water-based backlit film and a preparation method of the flame-retardant glue, and belongs to the technical field of flame-retardant glue.The flame-retardant glue is prepared from, by weight, 81.3%-85.5% of gelatin powder, 2.3%-4.6% of phytic acid-based flame retardant, 8.4%-11.2% of chitin / BMIMAc ionic gel and the balance filler particles; the phytic acid based flame retardant is dopamine modified sodium phytate; the flame-retardant glue is prepared from the gelatin powder, the dopamine modified sodium phytate, the chitin / BMIMAc ionic gel and the filler particles, due to the fact that the main components such as the gelatin powder, the dopamine modified sodium phytate and the chitin have biodegradability, pollution to the environment is reduced, and the flame-retardant glue has good environmental friendliness and biological safety; the dopamine is used for modifying sodium phytate, and the chitin / BMIMAc ionic gel is prepared by a radiation crosslinking method, so that the flame-retardant effect, the water resistance and the weather resistance of the flame-retardant glue are improved.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant glue, and in particular to a water-based flame retardant glue for back-sprayed lamp sheets and a preparation method thereof. Background Art

[0002] Water-based back-jet light film is a printing material used in advertising display, decoration and other fields. It is generally composed of a film base (such as PET) and a coating. After printing on the back with water-based ink, a clear and bright image can be presented on the front.

[0003] During the installation process, water-based back-sprayed light sheets need to be fixed with glue. Since the main components of water-based back-sprayed light sheets are polymer materials such as polyester (PET), they are easily ignited and burned when encountering a fire source. Using flame-retardant glue to enhance the flame-retardant effect of water-based back-sprayed light sheets has many benefits, such as improving safety performance, protecting equipment and the environment.

[0004] For example, invention patent CN107573528A discloses a flame retardant glue for water-based back-spray lamp sheets and a preparation method thereof, the ingredients of which are: 10-17% phosphorus-containing acrylic monomer, 0.1-0.5% nitric acid, 3-8% melamine, 3-8% curing agent, 2-4% initiator, 62-81.8% acrylic glue and 0.1-0.5% sodium diisooctyl succinate sulfonate.

[0005] However, flame-retardant glue still has the following problems that need to be solved urgently: First, it has poor biodegradability and is difficult to be decomposed by microorganisms in the natural environment. Long-term accumulation will pose a threat to the ecological environment. Second, water resistance and weather resistance need to be further improved. In humid environments and complex climatic conditions, the performance of glue is easily affected, resulting in reduced bonding strength and weakened flame retardant effect. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a water-based flame retardant glue for back-sprayed lamp sheets and a preparation method thereof.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A water-based flame-retardant glue for back-sprayed lamp sheets comprises the following raw materials, measured in percentage by weight: 81.3-85.5% of gelatin powder, 2.3-4.6% of a phytic acid-based flame retardant, 8.4-11.2% of a chitosan / BMIMAc ion gel and the remainder of filler particles; the phytic acid-based flame retardant is dopamine-modified sodium phytate; the chitosan / BMIMAc ion gel is prepared from BMIMAC ionic liquid and chitosan by using a radiation cross-linking method.

[0008] Furthermore, the preparation method of dopamine-modified sodium phytate is as follows: by weight, 11.3-15.4 parts of sodium phytate are added to deionized water, stirred to fully dissolve it, and a 10-15.8% sodium phytate solution is formed; 1-2.3 parts of dopamine hydrochloride are weighed, dissolved in a Tris-HCl buffer solution, stirred to fully dissolve it, and a 2.5-3.8% dopamine solution is formed; the sodium phytate solution is slowly added to the dopamine solution, and placed in a microwave reaction tube, and then the microwave reaction tube is placed in a microwave reactor, the microwave power is 300-500W, the reaction temperature is 45-58°C, and the time is 5-10h; dopamine is fully self-polymerized and fully combined with sodium phytate to achieve the modification of sodium phytate; then the product is centrifuged and placed in a freeze dryer for freeze drying to obtain dopamine-modified sodium phytate.

[0009] Furthermore, the product is centrifuged at 3000-5000 r / min for 5-10 minutes.

[0010] Furthermore, the preparation method of chitosan / BMIMAc ion gel is as follows: chitosan and BMIMAc ionic liquid (1-butyl-3-methylimidazolium acetate) with a purity of ≥98% are weighed by weight, 10-15 parts of chitosan are added to 30-50 parts of BMIMAc ionic liquid, and the mixture is stirred at 55-65°C for 1.5-3h to fully mix the chitosan and BMIMAc ionic liquid; the mixed solution is placed under a radiation source for radiation treatment, the radiation dose is 45-68kGy, and the radiation time is 2-3h; after the radiation cross-linking is completed, the obtained ion gel is washed with water to remove unreacted chitosan, BMIMAc ionic liquid and possible by-products, and finally the ion gel is dried at 50-55°C to obtain the chitosan / BMIMAc ion gel.

[0011] Furthermore, the radiation source uses gamma rays or electron beams.

[0012] Furthermore, the filler particles include the following raw materials in weight percentage: 26-40% starch and the balance light calcium carbonate.

[0013] In order to better achieve the purpose of the present invention, the present invention also provides a method for preparing a water-based flame retardant glue for back-sprayed lamp sheets, comprising the following steps: Step (1): dissolving gelatin powder in 5 to 10 times the mass of water, adding filler particles and stirring evenly to form a mixture A; Step (2): mixing the phytic acid-based flame retardant with the chitosan / BMIMAc ion gel at room temperature for 10 to 15 minutes to form a mixture B; Step (3): Add mixture B dropwise to mixture A while stirring, and continue stirring for 20 to 30 minutes after the addition is completed; Step (4): The obtained product is then subjected to vacuum degassing treatment to obtain a water-based flame retardant glue for back-sprayed lamp sheets.

[0014] Furthermore, the dripping speed is controlled at 2 to 4 drops / s.

[0015] Furthermore, in step (4), the obtained product is subjected to vacuum degassing treatment and then placed at a low temperature of 5 to 10° C. for 1 to 2 hours to obtain a water-based flame retardant glue for back-spray lamp sheets.

[0016] In order to better achieve the purpose of the present invention, the present invention also provides a water-based flame-retardant glue for back-sprayed light sheets prepared according to the preparation method.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the present invention is prepared by gelatin powder, dopamine-modified sodium phytate, chitosan / BMIMAc ion gel and filler particles; since the main components of gelatin powder, dopamine-modified sodium phytate, chitosan and the like are all biodegradable, it is beneficial to reduce pollution to the environment, and the flame retardant glue has good environmental friendliness and biosafety; the present invention uses dopamine-modified sodium phytate, and the chitosan / BMIMAc ion gel is prepared by a radiation crosslinking method, which is beneficial to improving the flame retardant effect, water resistance and weather resistance of the flame retardant glue. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1: Preparation of dopamine-modified sodium phytate: 11.3 parts of sodium phytate were added to deionized water by weight, and stirred to fully dissolve it to form a 15.8% sodium phytate solution; 1 part of dopamine hydrochloride was weighed, dissolved in a Tris-HCl buffer solution, and stirred to fully dissolve it to form a 3.8% dopamine solution; the sodium phytate solution was slowly added to the dopamine solution and placed in a microwave reaction tube, and then the microwave reaction tube was placed in a microwave reactor with a microwave power of 300 W, a reaction temperature of 58° C., and a reaction time of 5 h; dopamine was fully self-polymerized and fully combined with sodium phytate to achieve the modification of sodium phytate; the product was then centrifuged at a speed of 5000 r / min for 5 minutes, and then placed in a freeze dryer for freeze drying to obtain dopamine-modified sodium phytate.

[0020] Example 2: Preparation of dopamine-modified sodium phytate: 15.4 parts of sodium phytate were added to deionized water by weight, and stirred to fully dissolve it to form a 10% sodium phytate solution; 2.3 parts of dopamine hydrochloride were weighed, dissolved in a Tris-HCl buffer solution, and stirred to fully dissolve it to form a 2.5% dopamine solution; the sodium phytate solution was slowly added to the dopamine solution and placed in a microwave reaction tube, and then the microwave reaction tube was placed in a microwave reactor with a microwave power of 500 W, a reaction temperature of 45° C., and a time of 10 h; dopamine was fully self-polymerized and fully combined with sodium phytate to achieve the modification of sodium phytate; the product was then centrifuged at a speed of 3000 r / min for 10 minutes, and then placed in a freeze dryer for freeze drying to obtain dopamine-modified sodium phytate.

[0021] Example 3: Preparation of dopamine-modified sodium phytate: Add 12 parts of sodium phytate by weight to deionized water, stir to fully dissolve it, and form a 13.5% sodium phytate solution; weigh 2 parts of dopamine hydrochloride, dissolve it in Tris-HCl buffer solution, stir to fully dissolve it, and form a 3% dopamine solution; slowly add the sodium phytate solution to the dopamine solution and put it into a microwave reaction tube, then put the microwave reaction tube into a microwave reactor, the microwave power is 400W, the reaction temperature is 48°C, and the time is 7h; dopamine fully self-polymerizes and fully combines with sodium phytate to achieve the modification of sodium phytate; then the product is centrifuged at a speed of 4000r / min for 8 minutes, and then placed in a freeze dryer for freeze drying to obtain dopamine-modified sodium phytate.

[0022] Example 4: Preparation of chitosan / BMIMAc ion gel: chitosan and BMIMAc ionic liquid (1-butyl-3-methylimidazolium acetate) with a purity of ≥98% are weighed by weight, 10 parts of chitosan are added to 50 parts of BMIMAc ionic liquid, and the mixture is stirred at 55°C for 3 hours to fully mix the chitosan and BMIMAc ionic liquid; the mixed solution is placed under a radiation source (γ rays can be used, which have strong penetrating ability and can evenly induce a cross-linking reaction) for radiation treatment, the radiation dose is 45 kGy, and the radiation time is 3 hours; after the radiation cross-linking is completed, the obtained ion gel is washed with water to remove unreacted chitosan, BMIMAc ionic liquid and possible by-products, and finally the ion gel is dried at 50°C to obtain the chitosan / BMIMAc ion gel.

[0023] Example 5: Preparation of chitosan / BMIMAc ion gel: chitosan and BMIMAc ionic liquid (1-butyl-3-methylimidazolium acetate) with a purity of ≥98% are weighed by weight, 15 parts of chitosan are added to 30 parts of BMIMAc ionic liquid, and the mixture is stirred at 65°C for 1.5 hours to fully mix the chitosan and BMIMAc ionic liquid; the mixed solution is placed under a radiation source (electron beam or the like can be used to induce the cross-linking reaction) for radiation treatment, the radiation dose is 68 kGy, and the radiation time is 2 hours; after the radiation cross-linking is completed, the obtained ion gel is washed with water to remove unreacted chitosan, BMIMAc ionic liquid and possible by-products, and finally the ion gel is dried at 55°C to obtain the chitosan / BMIMAc ion gel.

[0024] Example 6: Preparation of chitosan / BMIMAc ion gel: chitosan and BMIMAc ionic liquid (1-butyl-3-methylimidazolium acetate) with a purity of ≥98% are weighed by weight, 12 parts of chitosan are added to 35 parts of BMIMAc ionic liquid, and the mixture is stirred and mixed at 58°C for 2 hours to fully mix the chitosan and BMIMAc ionic liquid; the mixed solution is placed under a radiation source (γ rays can be used, which have strong penetrating ability and can evenly induce a cross-linking reaction) for radiation treatment, the radiation dose is 50 kGy, and the radiation time is 2.5 hours; after the radiation cross-linking is completed, the obtained ion gel is washed with water to remove unreacted chitosan, BMIMAc ionic liquid and possible by-products, and finally the ion gel is dried at 52°C to obtain the chitosan / BMIMAc ion gel.

[0025] Embodiment 7: A method for preparing a water-based flame-retardant glue for back-sprayed lamp sheets, comprising the following steps: Step (1): weigh 81.3 g of gelatin powder, 4.6 g of dopamine-modified sodium phytate (prepared in Example 1), 8.4 g of chitosan / BMIMAc ion gel (prepared in Example 4), and 5.7 g of filler particles (1.48 g of starch and 4.22 g of light calcium carbonate); Step (2): dissolving gelatin powder in 5 times the mass of water, adding filler particles and stirring evenly to form a mixture A; Step (3): mixing the phytic acid-based flame retardant and the chitosan / BMIMAc ion gel at room temperature for 10 minutes to form a mixture B; Step (4): Add mixture B dropwise to mixture A while stirring, and control the dropping speed at 2 drops / s. Continue stirring for 30 minutes after the dropping is completed; Step (5): The obtained product is then subjected to vacuum degassing treatment, and then placed at a low temperature of 5° C. for 2 hours to obtain a water-based flame retardant glue for back-spray lamp sheets.

[0026] Embodiment 8: A method for preparing a water-based flame-retardant glue for back-sprayed lamp sheets, comprising the following steps: Step (1): weigh 85.5 g of gelatin powder, 2.3 g of dopamine-modified sodium phytate (prepared in Example 2), 11.2 g of chitosan / BMIMAc ion gel (prepared in Example 5), and 1 g of filler particles (0.4 g of starch and 0.6 g of light calcium carbonate); Step (2): dissolving gelatin powder in 10 times the mass of water, adding filler particles and stirring evenly to form a mixture A; Step (3): mixing the phytic acid-based flame retardant and the chitosan / BMIMAc ion gel at room temperature for 15 minutes to form a mixture B; Step (4): Add mixture B dropwise to mixture A while stirring, and control the dropping speed at 4 drops / s. Continue stirring for 20 minutes after the dropping is completed; Step (5): The obtained product is then subjected to vacuum degassing treatment, and then placed at a low temperature of 10° C. for 1 hour to obtain a water-based flame retardant glue for back-spray lamp sheets.

[0027] Embodiment 9: A method for preparing a water-based flame-retardant glue for back-sprayed lamp sheets, comprising the following steps: Step (1): weigh 82 g of gelatin powder, 3 g of dopamine-modified sodium phytate (prepared in Example 3), 10 g of chitosan / BMIMAc ion gel (prepared in Example 6), and 5 g of filler particles (1.5 g of starch and 3.5 g of light calcium carbonate); Step (2): dissolving gelatin powder in 6 times the mass of water, adding filler particles and stirring evenly to form a mixture A; Step (3): mixing the phytic acid-based flame retardant and the chitosan / BMIMAc ion gel at room temperature for 12 minutes to form a mixture B; Step (4): Add mixture B dropwise to mixture A while stirring. The dropping speed is controlled at 3 drops / s. After the dropping is completed, continue stirring for 25 minutes. Step (5): The obtained product is then subjected to vacuum degassing treatment, and then placed at a low temperature of 8° C. for 1.2 hours to obtain a water-based flame retardant glue for back-spray lamp sheets.

[0028] Comparative Example 1: Different from Example 9, dopamine-modified sodium phytate was replaced by sodium phytate.

[0029] Comparative Example 2: Different from Example 9, the preparation method of chitosan / BMIMAc ion gel is as follows: weigh chitosan and BMIMAC ionic liquid (1-butyl-3-methylimidazolium acetate) with a purity of ≥98%, add 10 parts of chitosan to 50 parts of BMIMAC ionic liquid, stir and mix at 55°C for 3h to fully mix the chitosan and BMIMAC ionic liquid to obtain chitosan / BMIMAc ion gel.

[0030] Experimental Example: The flame retardant glue prepared in Examples 7 to 9 and Comparative Examples 1 to 2 was tested for performance, including: Flame retardant performance: UL 94-2006 standard.

[0031] Bonding strength: Flame retardant glue is applied on the water-based flame retardant backspray lamp sheet, and a glue layer is formed after drying, with a dry weight of 12g / m2, and the bonding strength is tested.

[0032] Water resistance: After the adhesive on the water-based flame retardant backspray lamp sheet is completely dry, put it into an aqueous solution containing 3.5% NaCl and 0.5% NaOH, heat it to 100°C and place it for 5 days to see the water whitening condition.

[0033] Weather resistance: After the adhesive on the water-based flame retardant backspray lamp sheet is completely dry, put it into a high and low temperature test box, first place it at 80°C for 1 day; then quickly cool it to -40°C and place it for 1 day; repeat this cycle 5 times, test the bonding strength, and observe the changes in the appearance of the glue layer.

[0034] Table 1 Performance test results of flame retardant glue As can be seen from Table 1, the present invention uses dopamine to modify sodium phytate, and the chitosan / BMIMAc ion gel is prepared by radiation cross-linking, which is beneficial to improving the flame retardant effect, water resistance and weather resistance of the flame retardant glue.

[0035] Sodium phytate contains phosphoric acid groups and has a flame retardant effect. Dopamine fully self-polymerizes to form polydopamine. Polydopamine contains a large number of amino and phenolic hydroxyl groups, has good dispersibility in the glue system, and can be stably combined with gelatin powder and other ingredients. During the combustion process, polydopamine can form a dense carbon layer, which synergizes with the insulating layer of sodium phytate to enhance the flame retardant effect. These groups of polydopamine can react with the hydroxyl and phosphoric acid groups of sodium phytate to enhance the bonding strength between polydopamine and sodium phytate. On the one hand, it can reduce the channels for water molecules to enter the glue, thereby improving water resistance; on the other hand, it can improve stability and thus improve the weather resistance of the glue. Chitosan and BMIMAC ionic liquids are cross-linked by radiation, which is conducive to increasing the cross-linking density. The network structure with high cross-linking density limits the movement of glue molecules, improves the cohesive strength and heat resistance of the glue, and helps to enhance the flame retardant effect. At the same time, the tight network structure formed by radiation cross-linking can, on the one hand, reduce the channels for water molecules to enter the glue, thereby improving water resistance; on the other hand, it is beneficial to block oxygen, ultraviolet rays, etc. in the external environment, reduce erosion of the glue, and help improve the weather resistance of the glue.

[0036] The invention is prepared by gelatin powder, dopamine-modified sodium phytate, chitosan / BMIMAc ion gel and filler particles. Since the main components of gelatin powder, dopamine-modified sodium phytate and chitosan are all biodegradable, it is beneficial to reduce pollution to the environment, and the flame retardant glue has good environmental friendliness and biosafety.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-based flame retardant glue for back-spray lamp sheets, characterized in that: The invention comprises the following raw materials, in percentage by weight: 81.3-85.5% of gelatin powder, 2.3-4.6% of phytic acid-based flame retardant, 8.4-11.2% of chitosan / BMIMAc ion gel and the remainder of filler particles; the phytic acid-based flame retardant is dopamine-modified sodium phytate; the chitosan / BMIMAc ion gel is prepared from BMIMAC ionic liquid and chitosan by using a radiation cross-linking method.

2. The water-based flame retardant glue for back-sprayed lamp sheets according to claim 1, characterized in that: The preparation method of dopamine-modified sodium phytate is as follows: by weight, 11.3-15.4 parts of sodium phytate are added to deionized water, stirred to fully dissolve it, and a 10-15.8% sodium phytate solution is formed; 1-2.3 parts of dopamine hydrochloride are weighed, dissolved in a Tris-HCl buffer solution, stirred to fully dissolve it, and a 2.5-3.8% dopamine solution is formed; the sodium phytate solution is slowly added to the dopamine solution and placed in a microwave reaction tube, and then the microwave reaction tube is placed in a microwave reactor, the microwave power is 300-500W, the reaction temperature is 45-58°C, and the time is 5-10h; dopamine is fully self-polymerized and fully combined with sodium phytate to achieve the modification of sodium phytate; then the product is centrifuged and then placed in a freeze dryer for freeze drying to obtain dopamine-modified sodium phytate.

3. The water-based flame retardant glue for back-sprayed lamp sheets according to claim 2, characterized in that: The product is centrifuged at 3000~5000r / min for 5~10 minutes.

4. The water-based flame retardant glue for back-sprayed lamp sheets according to any one of claims 1 to 3, characterized in that: The preparation method of chitosan / BMIMAc ion gel is as follows: chitosan and BMIMAC ionic liquid with a purity of ≥98% are weighed by weight, 10-15 parts of chitosan are added to 30-50 parts of BMIMAC ionic liquid, and the mixture is stirred at 55-65° C. for 1.5-3 hours to fully mix the chitosan and the BMIMAC ionic liquid; the mixed solution is placed under a radiation source for radiation treatment, the radiation dose is 45-68 kGy, and the radiation time is 2-3 hours; after the radiation cross-linking is completed, the obtained ion gel is washed with water, and finally the ion gel is dried at 50-55° C. to obtain the chitosan / BMIMAc ion gel.

5. The water-based flame retardant glue for back-sprayed lamp sheets according to claim 4, characterized in that: The radiation source is either gamma rays or electron beams.

6. The water-based flame retardant glue for back-sprayed lamp sheets according to claim 1, characterized in that: The filler particles include the following raw materials, measured by weight percentage: 26-40% starch and the balance light calcium carbonate.

7. A method for preparing the water-based flame retardant glue for back-sprayed lamp sheets according to claim 4, characterized in that: The following steps are involved: Step (1): dissolving gelatin powder in 5 to 10 times the mass of water, adding filler particles and stirring evenly to form a mixture A; Step (2): mixing the phytic acid-based flame retardant with the chitosan / BMIMAc ion gel at room temperature for 10 to 15 minutes to form a mixture B; Step (3): Add mixture B dropwise to mixture A while stirring, and continue stirring for 20 to 30 minutes after the addition is completed; Step (4): The obtained product is then subjected to vacuum degassing treatment to obtain a water-based flame retardant glue for back-sprayed lamp sheets.

8. The method for preparing the water-based flame retardant glue for back-sprayed lamp sheets according to claim 7, characterized in that: The dropping speed is controlled at 2~4 drops / s.

9. The method for preparing the water-based flame retardant glue for back-sprayed lamp sheets according to claim 8, characterized in that: In step (4), the obtained product is subjected to vacuum degassing treatment and then placed at a low temperature of 5 to 10° C. for 1 to 2 hours to obtain a water-based flame retardant glue for back-spray lamp sheets.

10. A water-based flame-retardant glue for back-sprayed light sheets prepared according to the preparation method according to claim 9.

Images