CN111662672A - Hydrophilic adhesive and synthesis method and application thereof - Google Patents

Abstract

The invention discloses a hydrophilic adhesive and a synthesis method and application thereof. The synthesis method comprises the following steps: the hydrophilic adhesive is formed by copolymerization reaction of a uniform mixed reaction system containing polyhydroxy polyether, polyhydroxy polyester and polyfunctional group isocyanate. The synthetic method of the hydrophilic adhesive is simple in process, and the obtained hydrophilic adhesive is coated on the wrapping layer of the non-woven fabric core body and then is attached to the core body. Because the adhesive is polar and hydrophilic, the wrapping layer of the non-woven fabric core body can still maintain certain hydrophilicity relative to a rubber adhesive after the core body absorbs urine and the hydrophilic agent of the wrapping layer of the non-woven fabric core body is eluted, so that the wrapping layer has better attaching and adhering properties to the core body material after water absorption, the core body after water absorption maintains certain physical wrapping property, the complete state of the core body can be maintained greatly, and the application prospect is wide.

Description

A kind of hydrophilic adhesive and its synthesis method and application

technical field

The invention relates to a hydrophilic adhesive, in particular to a hydrophilic adhesive applied to the core of a diaper which is formed by wrapping wood pulp and a water-absorbing polymer in a non-woven fabric, and a method for synthesizing the same, and applications thereof.

Background technique

A key component of the construction of a baby or adult diaper is the core that absorbs urine. In the production process, diaper manufacturers effectively mix water-absorbent resin and wood pulp fiber, and use the mixture of water-absorbent resin and wood pulp fiber as the core. The traditional core is a mixture of polymer water-absorbing resin and wood pulp fiber, which is wrapped with clean paper and non-woven fabric after molding and integrated into the diaper structure. The core body wrapped with non-woven fabric is softer and thinner than the core body wrapped with dust-free paper. The non-woven fabric is bonded to the core with a rubber-based hot melt adhesive, which plays a wrapping role. However, the weakness of the core wrapped by the non-woven fabric is that after absorbing urine, the non-woven fabric and rubber-based hot melt adhesive both show non-polar and non-hydrophilic properties due to the elution of the hydrophilic treatment agent on the surface of the non-woven fabric fiber. Therefore, it is difficult to maintain a tight fit with the liquid-absorbing core wood pulp and the high-molecular water-absorbent resin. Thus, the wrapping layer no longer has a physical wrapping effect on the material of the core. The wood pulp and water-absorbent resin in the core are in the form of dispersed particles after absorbing water. When the physical wrapping function fails, it is very easy to spread out, resulting in a stacking phenomenon, which is manifested as a fault in the core of the diaper. For users, it is a very poor experience.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a hydrophilic adhesive and its synthesis method and application to overcome the deficiencies of the prior art.

In order to realize the foregoing invention purpose, the technical scheme adopted in the present invention includes:

An embodiment of the present invention provides a method for synthesizing a hydrophilic adhesive, which includes: copolymerizing a uniformly mixed reaction system comprising polyhydroxy polyether, polyhydroxy polyester and multifunctional isocyanate to form a hydrophilic adhesive.

In some embodiments, the polyhydroxy polyether includes any one or a combination of two or more of difunctional polyethylene glycol, difunctional polypropylene glycol, and trifunctional polypropylene glycol.

In some embodiments, the polyhydroxy polyester includes difunctional polyethylene adipate, difunctional polypropylene adipate, difunctional polyneopentyl adipate, difunctional polyethylene phthalate Any one or a combination of two or more of diols, difunctional polypropylene phthalate, and difunctional polyneopentyl phthalate.

Further, the multifunctional isocyanate includes MDI.

The embodiment of the present invention also provides a hydrophilic adhesive synthesized by the aforementioned method, which comprises a copolymer formed by the copolymerization reaction of polyhydroxy polyether, polyhydroxy polyester and polyfunctional isocyanate.

The embodiments of the present invention also provide the application of the aforementioned hydrophilic adhesive in the field of making baby or adult diapers.

Further, the application includes: applying the hydrophilic adhesive on the non-woven core wrapping layer, so that the non-woven fabric core wrapping layer is attached to the core body.

Compared with the prior art, the advantages of the present invention include:

The synthetic method of the hydrophilic adhesive provided by the invention is simple in process, and the obtained hydrophilic adhesive is coated on the non-woven core body wrapping layer and then attached to the core body. Since the adhesive of the present invention is polar and hydrophilic, after the core absorbs urine and the hydrophilic agent of the non-woven core wrapping layer is eluted, relative to the rubber-based adhesive, the wrapping layer can still maintain a certain hydrophilicity Therefore, the wrapping layer has better adhesion and adhesion performance to the core material after water absorption, so that the core body after water absorption maintains a certain physical wrapping performance, and it is more likely to maintain the integrity of the core body.

Detailed ways

As mentioned above, in view of the defects of the prior art, the inventor of the present case has been able to propose the technical solution of the present invention after long-term research and extensive practice, which mainly provides a hydrophilic adhesive, which is coated on the non-woven wrapping layer Then, fit with the core body. Since the adhesive is polar and hydrophilic, after the core absorbs urine and the hydrophilic agent of the non-woven wrapping layer is eluted, the wrapping layer can still maintain a certain degree of hydrophilicity compared with the rubber-based adhesive, thus, The wrapping layer has a certain adhesion to the core body, so that the core body has a greater possibility to remain intact. The technical solution, its implementation process and principle will be further explained as follows.

As one aspect of the technical solution of the present invention, it relates to a method for synthesizing a hydrophilic adhesive, which comprises: copolymerizing a uniformly mixed reaction system comprising polyhydroxy polyether, polyhydroxy polyester and polyfunctional isocyanate to form Polar hydrophilic adhesive.

In some embodiments, the polyhydroxy polyether includes any one or a combination of two or more prepolymers such as difunctional polyethylene glycol, difunctional polypropylene glycol, and trifunctional polypropylene glycol, but is not limited thereto.

Further, the mass average molecular weight of the polyhydroxy polyether is 1000-5000.

In some embodiments, the polyhydroxy polyester includes difunctional polyethylene adipate, difunctional polypropylene adipate, difunctional polyneopentyl adipate, difunctional polyethylene phthalate Any one or a combination of two or more of diols, bifunctional polypropylene phthalate, and bifunctional polyneopentyl phthalate systems, etc., but not limited thereto.

Further, the mass average molecular weight of the polyhydroxy polyester is 1000-3000.

In some embodiments, MDI is selected as the multifunctional isocyanate, but not limited thereto.

In some embodiments, the uniformly mixed reaction system includes the following components calculated by mass percentage: 25-65 wt % polyhydroxy polyether, 29-60 wt % polyhydroxy polyester and 6-15 wt % MDI.

In some embodiments, the temperature of the copolymerization reaction is 60-160° C., and the time is 0.5-4 h.

As another aspect of the technical solution of the present invention, the related hydrophilic adhesive is synthesized by the aforementioned method, which includes a copolymer formed by the copolymerization reaction of polyhydroxy polyether, polyhydroxy polyester and polyfunctional isocyanate.

Further, the viscosity of the hydrophilic adhesive at a temperature of 160° C. is 500-20,000 cps.

Another aspect of the embodiments of the present invention also provides the application of the aforementioned hydrophilic adhesive in the field of making baby or adult diapers.

Further, the application includes: applying the hydrophilic adhesive on the non-woven core wrapping layer, so that the non-woven fabric core wrapping layer is attached to the core body.

Further, the application includes: applying the hydrophilic adhesive to the non-woven core wrapping layer by at least any one of application methods such as squeegee, glue dispensing, and glue spraying.

With the above technical solutions, the synthetic method of the hydrophilic adhesive provided by the present invention is simple in process. Since the adhesive of the present invention is polar and hydrophilic, after the core absorbs urine and the hydrophilic agent of the non-woven core wrapping layer is eluted, relative to the rubber-based adhesive, the wrapping layer can still maintain a certain hydrophilicity Therefore, the wrapping layer has better adhesion and adhesion performance to the core material after water absorption, so that the core body after water absorption maintains a certain physical wrapping performance, and it is more likely to maintain the integrity of the core body.

The technical solutions of the present invention are further described in detail below through several embodiments. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Example 1

100 g of difunctional polyethylene adipate polyester with molecular weight of 3000, 180 g of difunctional polyethylene glycol polyether with molecular weight of 3000, 30 g of trifunctional polypropylene glycol polyether with molecular weight of 5000, and polyoxyethylene with molecular weight of 1600 30 g of ethylene phthalate polyester and 35 g of MDI were mixed uniformly and reacted at 120° C. for 1 hour.

After testing, the viscosity of the synthetic product hydrophilic adhesive obtained in this example at 160° C. is 5600.

At 140°C, the hydrophilic adhesive of the synthetic product obtained in this example was coated and sizing on the surface of the non-woven fabric, and was attached to the surface of the core material mixed with wood pulp and water-absorbing polymer to form an effective attachment.

test case

Also use commercially available rubber-based hot-melt adhesive to coat the non-woven surface samples for comparison. The bonding area is 5 cm * 5 cm. Use 150 ml of normal saline and pour it on the bonding site. After all the normal saline is absorbed, remove the non-woven fabric.

On the rubber-based coated surface, the wood pulp and water-absorbing polymer on the surface are easy to fall off after rubbing, while the hydrophilic adhesive of this embodiment is difficult to fall off after rubbing.

After all the wood pulp and water-absorbing polymer bonded by the hydrophilic adhesive were removed, the two samples were again bonded to the surface of the core that had absorbed water. Combining wood pulp and water-absorbing polymers. On the other hand, the surface of the hydrophilic adhesive of this embodiment is covered with wood pulp and water-absorbing polymers again.

Therefore, it can be seen that the hydrophilic adhesive of this embodiment has better adhesion and adhesion performance to the core material after water absorption, thereby maintaining a certain physical wrapping performance for the core body after water absorption, and maintaining the integrity of the core body.

Example 2

100 g of bifunctional polyethylene adipate polyester with molecular weight of 3000, 40 g of bifunctional polyethylene glycol polyether with molecular weight of 3000, 20 g of trifunctional polypropylene glycol polyether with molecular weight of 5000, and bifunctional with molecular weight of 4000 20 g of agglomerated propylene glycol polyether and 15 g of MDI were mixed uniformly and reacted at 90° C. for 2 hours.

At 140°C, the hydrophilic adhesive of the synthetic product obtained in this example was dispensed on the surface of the non-woven fabric using a 0.6 mm needle, and then adhered to the surface of the core material mixed with wood pulp and water-absorbing polymer to form an effective sticker. combine.

Example 3

Mix 100 g of difunctional polyethylene adipate polyester with a molecular weight of 2000, 50 g of difunctional polypropylene glycol polyether with a molecular weight of 1000, 150 g of trifunctional polypropylene glycol polyether with a molecular weight of 5000, and 40 g of MDI. The reaction was carried out at °C for 0.5 hour, and then the temperature was raised to 140 °C for 1 hour. The resulting adhesive can be coated on a substrate at 160°C. Use pure water droplets on the surface of the adhesive layer, the water droplets can spread and wet the surface of the adhesive layer. For the coated rubber-based adhesive, the water droplets do not spread on the surface and do not wet.

Example 4

Mix 142 g of difunctional polyethylene adipate polyester with a molecular weight of 1000, 40 g of difunctional polypropylene glycol polyether with a molecular weight of 4000, 20 g of trifunctional polypropylene glycol polyether with a molecular weight of 5000, and 22 g of MDI. The reaction was carried out at °C for 2 hours. The formed adhesive can be coated on the substrate at 120°C. Use pure water droplets on the surface of the adhesive layer, the water droplets can spread and wet the surface of the adhesive layer. For the coated rubber-based adhesive, the water droplets do not spread on the surface and do not wet.

Example 5

Mix 85 g of difunctional polyethylene adipate polyester with a molecular weight of 3000, 130 g of difunctional polypropylene glycol polyether with a molecular weight of 4000, 60 g of trifunctional polypropylene glycol polyether with a molecular weight of 5000, and 18 g of MDI. After the reaction was carried out at 140°C for 1 hour, the temperature was gradually raised to 140°C for 3 hours, and the formed adhesive could be coated on the substrate at 140°C. Use pure water droplets on the surface of the adhesive layer, the water droplets can spread and wet the surface of the adhesive layer. For the coated rubber-based adhesive, the water droplets do not spread on the surface and do not wet.

Example 6

100 g of bifunctional polyethylene adipate polyester with molecular weight of 3000, 40 g of bifunctional polyethylene glycol polyether with molecular weight of 3000, 20 g of trifunctional polypropylene glycol polyether with molecular weight of 5000, and bifunctional with molecular weight of 4000 20 g of agglomerated propylene glycol polyether and 15 g of MDI were mixed uniformly and reacted at 160° C. for 0.5 hour.

At 140°C, the hydrophilic adhesive of the synthetic product obtained in this example was dispensed on the surface of the non-woven fabric using a 0.6 mm needle, and then adhered to the surface of the core material mixed with wood pulp and water-absorbing polymer to form an effective sticker. combine.

To sum up, with the above technical solutions of the present invention, the hydrophilic adhesive of the present invention is applied to the non-woven fabric wrapping layer and then attached to the core. Since the adhesive is polar and hydrophilic, after the core absorbs urine and the hydrophilic agent of the non-woven wrapping layer is eluted, relative to the rubber-based adhesive, the wrapping layer can still maintain a certain degree of hydrophilicity, so that the The wrapping layer has a certain adhesion force to the core, which makes the core more likely to remain intact, and has wide application prospects.

In addition, the inventors of the present application also carried out tests with other raw materials and conditions listed in this specification with reference to the methods of Examples 1 to 6, and also obtained polar and hydrophilic products, so that the wrapping layer has a positive effect on the core body. A hydrophilic adhesive with a certain adhesive force that makes the core more likely to remain intact.

It should be understood that the above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. A method for synthesizing a hydrophilic adhesive is characterized by comprising the following steps: the hydrophilic adhesive is formed by copolymerization reaction of a uniform mixed reaction system containing polyhydroxy polyether, polyhydroxy polyester and polyfunctional group isocyanate.

2. The method of synthesis according to claim 1, characterized in that: the polyhydroxy polyether comprises any one or the combination of more than two of difunctional polyethylene glycol, difunctional polypropylene glycol and trifunctional polypropylene glycol; and/or the mass average molecular weight of the polyhydroxy polyether is 1000-5000.

3. The method of synthesis according to claim 1, characterized in that: the polyhydroxy polyester comprises any one or the combination of more than two of difunctional poly (ethylene adipate) glycol, difunctional poly (propylene adipate) glycol, difunctional poly (neopentyl adipate) glycol, difunctional poly (ethylene phthalate) glycol, difunctional poly (propylene phthalate) glycol and difunctional poly (neopentyl phthalate); and/or the mass average molecular weight of the polyhydroxy polyester is 1000-3000.

4. The method of synthesis according to claim 1, characterized in that: the polyfunctional isocyanate comprises MDI.

5. The synthesis method of claim 1, wherein the homogeneous mixing reaction system comprises the following components in percentage by mass: 25-65 wt% of polyhydroxy polyether, 29-60 wt% of polyhydroxy polyester and 6-15 wt% of MDI.

6. The method of synthesis according to claim 1, characterized in that: the temperature of the copolymerization reaction is 60-160 ℃, and the time is 0.5-4 h.

7. A hydrophilic adhesive synthesized by the method of any one of claims 1-6 comprising a copolymer formed by copolymerization of a polyhydroxy polyether, a polyhydroxy polyester, and a polyfunctional isocyanate.

8. The hydrophilic adhesive of claim 7, wherein: the viscosity of the hydrophilic adhesive is 500-20000 cps at 160 ℃.

9. Use of the hydrophilic adhesive of claim 7 or 8 in the field of baby or adult diaper manufacture.

10. The application according to claim 9, wherein the application comprises: applying the hydrophilic adhesive to the non-woven fabric core body wrapping layer to enable the non-woven fabric core body wrapping layer to be attached to the core body; preferably, the application comprises: and applying the hydrophilic adhesive on the non-woven fabric core wrapping layer by adopting any one of glue scraping, glue dispensing and glue spraying.