CN101220252A - A kind of solid glue stick and preparation method thereof - Google Patents

Abstract

The invention discloses a solid glue stick, and is prepared with watercraft polyurethane latex as a major glue component, water as solvent, sodium stearate as gel, and polyvinyl alcohol and polyethylene pyrrole azululanone as accessory ingredients, and moderate glycerol added as humectant, wherein a self-emulsion method is adopted for the preparation of the watercraft polyurethane latex. The solid glue stick has the advantages that coated surface of the watercraft polyurethane adhesive adopted in preparing the solid glue stick is not easy to be damaged; the mechanical property is excellent; the modification is easy; the compatibility with paint is good; the prepared solid glue stick has obvious advantages in properties of assigned model, hardness, coating, and splicing, etc.; the appearance is pure white; the feeling is subtle; the splicing property is good; the drying speed is high; time for paper tearing is less than one minute; the hydrating period is as long as one year; the reserve property is fine.

Description

A kind of solid glue stick and preparation method thereof

technical field

The invention relates to a solid glue stick, in particular to a solid glue stick with water-based polyurethane as an adhesive component.

Background technique

Solid glue stick is also called solid glue. Compared with liquid glue, solid glue stick is not only easy to carry, but also does not flow or stick to hands, so it is very popular. The main raw material of solid glue stick is paper adhesive, and some substances that are easy to solidify and form are added as gel, and then humectants, plasticizers and fragrances are added to improve its use, storage, smell and appearance. performance. The above-mentioned various raw materials are fully mixed according to the selected formula through a certain process, dispersed evenly, and then poured into a lipstick-type packaging container for cooling and molding to obtain a solid glue stick. To make a solid glue stick with excellent performance, the key is to select the appropriate raw materials and additives, and to determine its optimal formulation and reaction conditions, and the most important thing is to select the appropriate adhesive.

As the main component of solid glue sticks, the choice of adhesive is crucial. An organic polymer compound with strong adhesive force, strong dispersing effect on water or water solubility, and easy to spread should be selected as the adhesive. At present, the commonly used solid glue stick adhesives at home and abroad include polyvinyl alcohol (PVA), hydroxymethyl cellulose, polyvinylpyrrolidone (PVP), polyvinyl formal, polymer resin mixture, starch, bone glue or gelatin. Among these raw materials, polyvinylpyrrolidone has a good sticking effect, but it is not easily soluble in water and easily soluble in organic solvents, which makes its cost higher; although starch and bone glue are cheap, they are easy to deteriorate and difficult to store; The texture of the glue stick made from alcohol is not fine and smooth, which affects the coating property during use.

The development and development of solid glue sticks first began abroad, and have a history of more than 70 years. The initial development of solid glue sticks is the solidification of liquid adhesives, which means that the adhesives can be used in solid form. With the continuous deepening and development of research, the adhesive used for bonding is also constantly updated. After decades of development, the research and application technology of foreign solid glue sticks has been relatively mature, and some companies have supplied solid glue products of various brands.

Polyvinyl alcohol and polyvinyl pyrrolidone are commonly used as adhesives in the world, and the glue sticks made can provide sufficient mechanical strength. On this basis, someone used water-soluble polymers as an adhesive and soap glue as an excipient to develop a solid glue stick with stronger bonding performance and mechanical strength. In addition to the main glue and gelling agent, some additives can also be added to improve the performance of the solid glue stick. The variety of additives added abroad is much more abundant than that in China, so the properties of the glue sticks made are more superior. The additives used abroad include thickeners, preservatives, pigments, fillers, flavors, antioxidants, resins, dextrins, cellulose, starch derivatives, etc. Among them, graphite, talc, TiO ₂ , high-dispersion Silica, colloidal clay, silicon ore, chalk, magnesium oxide and glass fiber are used as pigments and fillers.

A solid glue stick developed in Germany, which is superior both in appearance and performance. The product has a transparent appearance, white and delicate texture, moderate hardness, short initial sticking time, strong adhesion, good silkiness and moisture retention, and can be used at room temperature. After being left for a year, it still has strong adhesion and moisture retention.

The research on domestic solid glue sticks starts relatively late, and develops also relatively slowly. At present, the country is mainly committed to researching the use of various raw materials as the adhesive for solid glue sticks, in order to achieve the best results in the comprehensive performance of solid glue sticks.

For example, although polyvinylpyrrolidone is effective as an adhesive for solid glue sticks, it is not easily soluble in water, has a high cost, and is not conducive to environmental protection. Although the cost of solid glue sticks made of polyvinyl alcohol-polyvinyl acetate emulsion is relatively low, the texture of these glue sticks is not delicate, the storage time is short, and a layer is formed on the surface of the glue stick in a short period of time (about one week). Thin film affects the applicability of use and has little practicability. The water-soluble polymer-soap solid agent of acyl anhydride base is mainly made into solid glue sticks although the storage time is long, but the initial sticking time is long and the cost is also high.

Duan Chengtian and Sun Yixiang (Shenyang Chemical Industry. 1994, (3): 8-10) used the ternary compound of white latex, water-soluble polymer containing acyl anhydride group and polyvinyl alcohol as composite adhesive to improve the solid glue stick. The initial tack time and storage time, and at the same time, due to the reduction of the amount of the polymer containing the acyl anhydride group, the production cost of the solid glue stick is also reduced. However, although the compounding of the above three adhesives has a certain synergistic effect, the proportion of the ternary composite adhesive must be appropriate, otherwise the three cannot be mixed uniformly. Later they added new additives (Shenyang Chemical Industry. 1995, (3): 12-13) to the above-mentioned solid glue stick again, containing RC ₆ H ₄ -OCH ₂ -CH ₂ -O in the polyhydric alcohol and molecular structure Compounds with _n structure are used as additives to improve the solidification performance of the solid agent, reduce the viscosity of the hot glue, and make the hot glue thick liquid easy to pour and form, which brings great convenience to production. However, the addition of new additives puts forward higher requirements for the ratio of raw materials.

Yin Heping (Guizhou Chemical Industry. 1998, (2): 22) developed a new type of solid glue stick for paper, repeatedly explored the synthesis process of the solid glue stick with bone glue or gelatin as adhesive, and found an optimal process route. Adopt bone glue and gelatin as adhesive, although raw material price is much lower than polyvinylpyrrolidone, water-dispersible polymeric resin and water-soluble or water-dispersible synthetic resin etc., but the solid glue stick that produces is easy to deteriorate, is difficult for storage.

Ming Shaofu (Journal of Natural Sciences of Heilongjiang University. 1995, 12 (1): 110-113) developed a multifunctional solid glue stick with polyvinyl alcohol and carboxymethyl cellulose as adhesives. This kind of solid adhesive is made of a variety of chemical raw materials with high molecular weight organic compounds as the main body. Performance tests have shown that it has the characteristics of strong adhesion, short bonding time, stable performance, and wide application. However, the texture of this glue stick is not delicate, which affects the spreadability during use.

Chai Yuanwu et al. (Chemical World. 1998, (6): 316-318) take stearates as gelling agent, polyvinyl acetate emulsion modified with polyvinyl alcohol as adhesive to prepare solid glue sticks, and use orthogonal experimental method The influence of the amount of gelling agent, adhesive, solvent and moisturizing agent on the product performance was tested, and the optimal formula and process conditions were determined. The solid glue stick made has good adhesion, and can reach the tear strength within 1 minute when kraft paper is glued, that is, the paper fiber is destroyed when peeled off, and the glue layer does not fall off.

In order to further improve product quality, reduce sales price, and meet market demand, many experts and technicians have adopted polyvinyl formal glue as the adhesive for solid glue sticks through a large number of experiments. The glue sticks made are not only sticky, but also smooth and delicate. , evenly coated.

Li Mingrong (Tianjin Chemical Industry. 1994, (3-4): 17-18) used polyvinyl formal as an adhesive, and agar and sodium stearate as a forming agent to develop an L-1 type solid glue stick. The solid glue stick has good adhesion and fast drying speed. Chen Yonghong et al. (China Adhesives. 2001, 10 (3): 21-23) studied the formula and process conditions for preparing solid glue sticks with polyvinyl alcohol, formaldehyde, urea, sodium stearate, etc. as the main raw materials, and the produced solid glue The stick is used for bonding various papers, and it reaches the tear strength after 2 minutes. After the product is naturally placed at room temperature for one year, all indicators are normal. On this basis, Hu Aizhu et al. (Henan Chemical Industry. 2000, (7): 11-12) used polyacrylamide modified polyvinyl formal as the main component of the adhesive, and sodium stearate with abundant sources as the excipient. Ethylene glycol was used as a humectant, and the influence of each component on the performance of the solid glue stick was studied, and a solid glue stick with better performance and low price was obtained. Yin Heping (Zhejiang Chemical Industry. 2005, 36(1): 23-25) used polyvinyl formal glue as an adhesive, used sodium stearate as an excipient, and added various indicators in the colloid to make Solid glue sticks in various bright colors, delicate appearance, moderate hardness, even and smooth application, high bonding strength and fast speed.

But now commercially available solid glue sticks still generally have the defects of low viscosity, stringiness and poor moisture retention, and there is also a certain gap in formability, storage stability and some application performance.

Contents of the invention

The purpose of this invention is to provide a kind of novel solid glue stick, this solid glue stick uses waterborne polyurethane as adhesive, the solid glue stick of making has good bonding performance, and drying speed is fast.

It is another object of the present invention to provide a method for preparing the above-mentioned solid glue stick.

The solid glue stick of the present invention is made of water-based polyurethane as the main glue component, water as the solvent, sodium stearate as the gelling agent, polyvinyl alcohol and polyvinylpyrrolidone as auxiliary agents, and an appropriate amount of moisturizing agent glycerin is added. The weight percentage of each raw material component consists of:

Water-based polyurethane emulsion 28～45%

Sodium stearate 7～12%

Water 30～45%

Glycerin 1～10%

Polyvinyl alcohol 0～8%

Polyvinylpyrrolidone 7-12%.

The preparation method of the solid glue stick of the present invention consists of three steps: the preparation of the aqueous polyurethane emulsion, the preparation of the gel and the preparation of the solid glue stick.

Wherein the preparation of aqueous polyurethane emulsion adopts self-emulsification method, this method introduces hydrophilic group on the polyurethane segment, utilizes its own hydrophilicity to carry out emulsification. This method does not add an emulsifier, but only relies on the hydrophilic group of the polyurethane structure to emulsify it. Specifically, it can be divided into two stages: the first stage is pre-stepwise polymerization, that is, the terminal -OH group on the molecular chain of the oligomer diol and the -NCO group in the diisocyanate (TDI) molecule are in accordance with a certain mass ratio reaction to obtain a small molecule polyurethane initial polymer with an end-NCO group, and then add a hydrophilic chain extender dimethylol propionic acid (DMPA) to the initial polymer for chain extension reaction. Introduce a hydrophilic -COOH group, and because the DMPA molecule contains two -OH groups, it can further react with the -NCO group in the initial polymer segment, thereby playing the role of chain extension and obtaining a molecular weight of 10 ³ The water-based polyurethane prepolymer; the second stage is the dispersion of the prepolymer in water. In order to improve the dispersion ability of the prepolymer in water, the salt-forming agent triethylamine is added to the prepolymer obtained in the first stage. Neutralize the reaction so that the pH value is between 7 and 8. At the same time, add water for high-speed stirring and shear emulsification to obtain a water-based polyurethane dispersion.

In the above synthesis reaction, the present invention selects polyether glycol N210 as the main raw material, and uses deionized water as the dispersion medium. First, dehydrate N210 under vacuum at 0.05-0.07Mpa and 110°C for 2 hours, cool to room temperature, add measured TDI to N210 according to the material ratio of n _NCO /n _OH = 2-2.5, and then add an appropriate amount of catalyst two For dibutyltin laurate, heat up to 80-85°C and react at a constant temperature for about 0.5h. Cool down to below 60°C, dissolve DMPA accounting for 5-6% of the total mass of N210 and TDI in an appropriate amount of N-methylpyrrolidone, then add it to the reaction system, and react at about 75°C for about 1 hour. Cool to about 40°C, under high-speed strong stirring, according to the amount of triethylamine and DMPA substance ratio of 1:1, slowly add triethylamine aqueous solution to emulsify and disperse, and continue stirring for about 30min until a uniform emulsion is obtained, that is It is a polyether type water-based polyurethane emulsion.

The preparation of gelling agent sodium stearate among the present invention is to prepare stearic acid and sodium hydroxide according to the mass ratio of 6.5～7:1, sodium hydroxide is dissolved in water, adds stearic acid and heating carries out neutralization reaction, Generate sodium stearate, which acts as a gelling agent (also known as excipient) for solid glue sticks. The response is as follows:

C ₁₇ H ₃₅ COOH+NaOH→C ₁₇ H ₃₅ COONa+H ₂ O

In the above preparation process, the neutralization reaction time of stearic acid and sodium hydroxide is 30 minutes, the neutralization reaction temperature is 80-85° C., and the pH value of the system after the reaction is terminated is 8-9.

The preparation process of the solid glue stick in the present invention is actually a simple physical uniform mixing process, and no chemical reaction occurs between various raw materials and auxiliary agents. Generally, solid glue sticks are composed of three types of substances with different functions: adhesive, gel and solvent, and an appropriate amount of additives are added to improve their performance in terms of use, storage, smell and appearance. The invention adopts water-based polyurethane emulsion as an adhesive, sodium stearate as a gelling agent, water as a solvent, and glycerin, polyvinyl alcohol and polyvinyl pyrrolidone as auxiliary agents to prepare a solid glue stick. Water-based polyurethane emulsion does not react with sodium stearate, they can be dissolved and compounded, and are suitable for making glue sticks.

The specific process is as follows: take an appropriate amount of stearic acid solid, heat and melt it on a water bath, and add an appropriate amount of water to stir evenly. Slowly add the calculated NaOH solution at 80-85°C, and stir for about 0.5h. Adjust the pH value of the material to about 8, add the weighed pre-water-based polyurethane emulsion, stir and mix, then add an appropriate amount of modification additives glycerin, polyvinyl alcohol and polyvinylpyrrolidone, stir to fully mix. Cool down to about 60°C, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and then a solid glue stick can be obtained.

In the present invention, the water-based polyurethane emulsion is used as an adhesive, sodium stearate is used as a gelling agent, and an appropriate humectant and auxiliary agent are added to prepare a solid glue stick. Since the water-based polyurethane adhesive is not easy to damage the surface to be painted, it has excellent mechanical properties and is easy to modify. The advantages of non-polluting, good compatibility with pigments, and superior comprehensive performance, the solid glue sticks made have obvious advantages in shaping, hardness, coating, bonding and other properties, and have broad development prospects and potential.

The production process of the solid glue stick of the present invention is simple, and the prepared glue stick has a white appearance, a delicate hand feeling, good bonding performance, fast drying speed, a paper tearing time of less than 1 minute, a moisturizing period of up to 1 year, and excellent storage performance.

Detailed ways

Example 1

Preparation of waterborne polyurethane emulsion

Weigh 100g of polyether N210 with Mn=1000, pour it into a four-necked flask equipped with a stirrer, a condenser, and a thermometer, vacuum dehydrate it at 0.05Mpa and 110°C for about 2 hours, cool to room temperature, add 35.5g of TDI, and then add two Drop the catalyst dibutyltin dilaurate, continue to heat up to 85°C, and react at constant temperature for 0.5h. Cool down to below 60°C, add 7.5g of DMPA dissolved in 20mL of N-methylpyrrolidone solution, and react at about 75°C for 1 hour. Mix 5.7g of triethylamine and 230mL of deionized water to make a triethylamine aqueous solution, and slowly add the triethylamine aqueous solution into the reaction system cooled to 40°C under high-speed strong stirring, and emulsify for 30 minutes to obtain a solid content of 45.3% water-based polyurethane emulsion.

Preparation of solid glue sticks

Weigh 5.2g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to about 70°C in a water bath to completely melt the stearic acid. Add 20 mL of deionized water, continue to heat up to 80° C., slowly add 8 g of 10% NaOH solution, stir and react for 0.5 h, and adjust the pH value of the material to about 8. Add 21g of preheated water-based polyurethane emulsion, stir and mix evenly, then add 5.4g of glycerin and 5.3g of polyvinylpyrrolidone, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and a solid glue stick with a solid content of 39.0% can be obtained.

Example 2

The preparation of aqueous polyurethane emulsion is with embodiment 1.

Preparation of solid glue sticks

Weigh 5.65g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to 70°C in a water bath to completely melt the stearic acid. Add 19 mL of deionized water, continue to heat up to 80° C., slowly add 8.69 g of 10% NaOH solution, stir and react for 0.5 h, and adjust the pH value of the material to about 8. Add 26g of preheated water-based polyurethane emulsion, stir and mix evenly, then add 3.0g of glycerin and 4.8g of polyvinylpyrrolidone, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and a solid glue stick with a solid content of 51.83% can be obtained.

Example 3

Preparation of waterborne polyurethane emulsion

Weigh 69.6g of polyether N210 (Mn=1000), pour it into a four-neck flask equipped with a stirrer, a condenser, and a thermometer, vacuum dehydrate it at 0.06Mpa and 110°C for about 2 hours, cool to room temperature, and add 24.3g of TDI , and then add two drops of catalyst dibutyltin dilaurate, continue to heat up to 85 ° C, constant temperature reaction 0.5h. Cool down to below 60°C, add 5.25g of DMPA dissolved in 15mL of N-methylpyrrolidone solution, and react at about 75°C for 1 hour. Mix 3.96g of triethylamine and 160mL of deionized water to make a triethylamine aqueous solution. Under high-speed strong stirring, slowly add the triethylamine aqueous solution into the reaction system cooled to 40°C, emulsify for 30 minutes, and obtain a solid content of 45.4% water-based polyurethane emulsion.

Preparation of solid glue sticks

Weigh 5g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to 70°C in a water bath to completely melt the stearic acid. Add 15mL of deionized water, continue to heat up to 80°C, slowly add 7.6g of 10% NaOH solution, stir and react for 0.5h, and adjust the pH value of the material to about 8. Add 22g of preheated water-based polyurethane emulsion, mix evenly, then add 4.2g of glycerin, 6.7g of polyvinylpyrrolidone and 3.3g of polyvinyl alcohol, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and then a solid glue stick with a solid content of 50.15% can be obtained.

Example 4

The preparation of aqueous polyurethane emulsion is with embodiment 3.

Preparation of solid glue sticks

Weigh 5.1 g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to 70° C. in a water bath to completely melt the stearic acid. Add 23mL of deionized water, continue to heat up to 80°C, slowly add 7.7g of 10% NaOH solution, stir and react for 0.5h, and adjust the pH value of the material to about 8. Add 20g of preheated water-based polyurethane emulsion, mix evenly, then add 1.2g of glycerin, 6.7g of polyvinylpyrrolidone and 4.8g of polyvinyl alcohol, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and a solid glue stick with a solid content of 45.98% can be obtained.

Example 5

Preparation of waterborne polyurethane emulsion

Weigh 66g of polyether N210 (Mn=1000), pour it into a four-necked flask equipped with a stirrer, condenser, and thermometer, dehydrate it under vacuum at 0.07Mpa and 110°C for about 2 hours, cool to room temperature, add 23g of TDI, and then Add two drops of catalyst dibutyltin dilaurate, continue to heat up to 85°C, and react at constant temperature for 0.5h. Cool down to below 60°C, add 15mL N-methylpyrrolidone solution dissolved with 4.9g DMPA, and react at about 75°C for 1h. Mix 3.7g of triethylamine and 100mL of deionized water to make a triethylamine aqueous solution, and slowly add the triethylamine aqueous solution into the reaction system cooled to 40°C under high-speed strong stirring, and emulsify for 30 minutes to obtain a solid content of 55% water-based polyurethane emulsion.

Preparation of solid glue sticks

Weigh 5.1 g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to 70° C. in a water bath to completely melt the stearic acid. Add 10 mL of deionized water, continue to heat up to 85° C., slowly add 7.7 g of 10% NaOH solution, stir and react for 0.5 h, and adjust the pH value of the material to about 8. Add 20g of preheated water-based polyurethane emulsion, mix evenly, then add 1.8g of glycerin, 6.2g of polyvinylpyrrolidone and 3.0g of polyvinyl alcohol, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and a solid glue stick with a solid content of 54.27% can be obtained.

Example 6

The preparation of aqueous polyurethane emulsion is with embodiment 5.

Preparation of solid glue sticks

Weigh 5g of stearic acid, add it into a four-necked flask equipped with a stirring device and a condenser, and heat it to 70°C in a water bath to completely melt the stearic acid. Add 10 mL of deionized water, continue to heat up to 85° C., slowly add 7.65 g of 10% NaOH solution, stir and react for 0.5 h, and adjust the pH value of the material to about 8. Add 22g of preheated water-based polyurethane emulsion, mix evenly, then add 3.4g glycerin and 3.75g polyvinylpyrrolidone, stir to make it fully mixed. Cool down to about 60°C, adjust the pH value to 8-9, pour the hot viscous liquid into a plastic tubular container with a rotary push button to cool and solidify, and then a solid glue stick can be obtained with a solid content of 49.71%.

Claims (6)

1. A solid glue stick, which is made of water-based polyurethane as the main glue component, water as the solvent, sodium stearate as the gelling agent, polyvinyl alcohol and polyvinylpyrrolidone as auxiliary agents, and an appropriate amount of moisturizing agent glycerin is added. , and the weight percent of each raw material component consists of: Water-based polyurethane emulsion 28～45% Sodium stearate 7～12% Water 30～45% Glycerin 1～10% Polyvinyl alcohol 0～8% Polyvinylpyrrolidone 7-12%. 2. the preparation method of the described solid glue stick of claim 1 is to prepare sodium stearate solution with NaOH solution and stearic acid, add the water-based polyurethane emulsion of preheating, then add modified auxiliary glycerol, polyvinyl alcohol and polyvinyl alcohol Vinylpyrrolidone, stirred to make it fully mixed, cooled to 60 ° C, poured into a plastic tube container with a rotary push button to cool and solidify, to obtain a solid glue stick. 3. the preparation method of solid glue stick according to claim 2 is characterized in that described polyurethane emulsion adopts self-emulsifying method to prepare. 4. the preparation method of solid glue stick according to claim 3 is characterized in that the preparation of described polyurethane emulsion is to make the small molecule polyurethane initial polymer of end-NCO group by polyether glycol N210 and diisocyanate reaction , and then add chain extender dimethylolpropionic acid to carry out chain extension reaction to obtain water-based polyurethane prepolymer, add salt-forming agent triethylamine to the prepolymer for neutralization reaction, add water at the same time and stir at high speed, shear emulsification, An aqueous polyurethane dispersion is obtained. 5. the preparation method of solid glue stick according to claim 4 is characterized in that the molar ratio of the substance of described triethylamine and dimethylol propionic acid is 1: 1. 6. the preparation method of solid glue stick according to claim 2 is characterized in that the preparation of described sodium stearate is stearic acid and sodium hydroxide with 6.5～7: 1 mass ratio reaction 0.5h, reaction The temperature is 80-85° C., and the pH value of the system is 8-9 after the reaction is terminated.