A new polymer gel material that can be used for soft rubber toys and its preparation process

Abstract

The present invention provides a gel material formed by hydrogen-bond thermal crosslinking of polyvinyl alcohol in an aqueous phase with lithium ions assisted by potassium ions, and a hydrogen-bond thermal crosslinking preparation process thereof, and proposes a scheme for preparing boron-free soft-gel toys with this hydrogen-bond thermal crosslinking gel material, wherein the gel material and the preparation process are characterized in that the main components of the gel are calculated by mass percentage, including: deionized water 60%-75.5%, polyvinyl alcohol 1750±50 9%-15%, water-soluble lithium ion source 7.5%-10%, and water-soluble potassium ion source 5%-7.5%. The hydrogen-bond thermal crosslinking gel material prepared by the present invention has the significant advantages of not containing or involving toxic and harmful substances, uniform components and less retention, simple preparation method and process, high degree of mechanical automation in the preparation process, high cleanliness, low production cost, energy saving and high efficiency, environmental friendliness, and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation and application, and in particular to the design and preparation of a non-toxic, low-residue viscoelastic polymer material and its application in the field of safety toys. Background Art

[0002] As a very popular type of toy in recent years, soft-gel toys account for about 10% of the children's toy market. At present, such toys are generally made of woodworking glue or daily glue added to medium-low concentration sodium tetraborate (borax) aqueous solution to form a gel material with boron atoms as the center and borate as the skeleton as the main body, and are prepared by artificially mixing other materials. This borate gel material has a very high market share in the soft-gel toy market. The target group of such toys is often primary and secondary school students and young children, and some have also entered the field of vision of office workers and parents.

[0003] However, toy materials with such a high market share have great safety risks. After conducting online and offline inspections of various stores selling slime toys, it was found that soft plastic toys with borate gel as the main material sold on the market have the following main defects:

[0004] (1) Existing soft plastic toys on the market use a lot of borax and woodworking glue and add propylene glycol as a water retaining agent. Borax has biological toxicity, cumulative toxicity and carcinogenicity. Formaldehyde is easily precipitated in some raw glues. Water retaining agents such as propylene glycol that can form boric acid esters will increase the retention of harmful substances on the hands, thus posing a hidden danger to the safety of children's toys. In this case, students and children are also prone to ingesting harmful substances.

[0005] (2) As the existing market has just begun to emerge, merchants have not fully defined this type of toys and the upstream raw material composition is not fixed. Therefore, the gel material composition of existing soft-gel toys on the market cannot be standardized and has no repeatability.

[0006] (3) The mixing preparation process of existing soft-gel toys on the market involves mixing several mixtures with each other, which can easily lead to defective products due to poor stability, incompatibility of raw materials due to different viscosities of raw materials, and uneven concentration of substances caused by insufficient local mixing.

[0007] (4) The mixing and preparation process of existing soft-gel toys on the market is mostly done manually, which makes it difficult to meet hygiene requirements such as the cleanliness level and total colony count of the final toy product.

[0008] (5) Gel materials with borate as the skeleton are also harmful to the environment. If soft-gel toys with this material as the main body are abandoned, it will be less friendly to the environment.

[0009] The technologies required for the above defects are the main gaps in the existing background technology of the current soft-gel toys and their main materials market, so it is difficult to produce standardized non-toxic soft-gel toy products.

[0010] In view of the above description, there is an urgent need for an environmentally friendly gel material that completely abandons the borate skeleton and has a high-safety fixed formula, and can be matched with a corresponding automated, clean and efficient preparation process. Summary of the invention

[0011] In view of the gap in the existing background technology of the above-mentioned soft rubber toys and their main materials market, the purpose of the present invention is to provide a hydrophilic gel material centered on non-toxic light metal ions and with hydrogen bond cross-linking as the skeleton, and to propose a hydrogen bond thermal cross-linking preparation process with fixed formula, automated production machinery and clean production process.

[0012] In order to achieve the above-mentioned purpose and the purpose of applying the material to other production research directions, the present invention provides a gel material formed by hydrogen-bond thermal crosslinking of polyvinyl alcohol in an aqueous phase with lithium ions assisted by potassium ions and a hydrogen-bond thermal crosslinking preparation process thereof, and proposes a scheme for preparing boron-free soft rubber toys using the hydrogen-bond thermal crosslinking gel material. The gel material and the preparation process are characterized by:

[0013] The main components of the gel are calculated by mass percentage and include:

[0014] Deionized water 60%-75.5%

[0015] Polyvinyl alcohol 1750±50 9%-15%

[0016] Water-soluble lithium ion source (lithium chloride monohydrate, other lithium-containing compounds converted according to the molar mass ratio of lithium ions) 7.5%-10%

[0017] Water-soluble potassium ion source (potassium chloride, other potassium-containing compounds converted according to the molar mass ratio of potassium ions) 5%-7.5%

[0018] Preferably, the main components of the gel include, by mass percentage:

[0019] Deionized water 75.5%

[0020] Polyvinyl alcohol 1750±50 9.5%

[0021] Water-soluble lithium ion source (lithium chloride monohydrate, other lithium-containing compounds calculated by lithium ion molar mass ratio) 7.5%

[0022] Water-soluble potassium ion source (potassium chloride, other potassium-containing compounds calculated by potassium ion molar mass ratio) 7.5%

[0023] The hydrogen bond thermal cross-linking preparation process of the gel comprises:

[0024] (1) Polyvinyl alcohol is dissolved in deionized water at a temperature between 70°C and 95°C under normal pressure to form a polyvinyl alcohol colloid without using formaldehyde and its aqueous solution or hydrochloric acid as a solvent.

[0025] (2) Using a water-soluble lithium ion source (lithium chloride monohydrate) at normal pressure and a temperature between 80°C and 90°C to preliminarily cross-link the polyvinyl alcohol colloid to form a polyvinyl alcohol gel solution.

[0026] (3) The gel material is obtained by completely cross-linking the polyvinyl alcohol gel using a water-soluble potassium ion source (potassium chloride) at a temperature between 60°C and 80°C under normal pressure.

[0027] (4) If the polyvinyl alcohol glue does not form a gel, vacuum distillation at 70°C-90°C can be used to induce the production of a gel material.

[0028] Preferably, the hydrogen bond thermal crosslinking preparation process of the gel material comprises:

[0029] (1) Polyvinyl alcohol is dissolved in deionized water at normal pressure and 92°C to form polyvinyl alcohol colloid without using formaldehyde and its aqueous solution or hydrochloric acid as a solvent.

[0030] (2) Using a water-soluble lithium ion source (lithium chloride monohydrate) at normal pressure and 85° C., the polyvinyl alcohol colloid is preliminarily cross-linked to form a polyvinyl alcohol gel.

[0031] (3) The gel material is obtained by completely cross-linking the polyvinyl alcohol gel using a water-soluble potassium ion source (potassium chloride) at normal pressure and 70°C.

[0032] (4) If the polyvinyl alcohol glue does not form a gel, the method of reduced pressure distillation at 87°C can be used to induce the production of gel material.

[0033] A method for preparing a soft rubber toy using the hydrogen bond thermal cross-linking gel material as the main body includes:

[0034] (1) Calculate in advance the required deionized water, polyvinyl alcohol 1750±50, water-soluble lithium ion source (lithium chloride monohydrate), water-soluble potassium ion source (potassium chloride), water-retaining agent, antibacterial agent, emulsifier, flavoring agent, and coloring agent according to the mass percentage of the main components of the gel.

[0035] (2) Polyvinyl alcohol is dissolved in deionized water at normal pressure and 92° C. to form polyvinyl alcohol colloid without using formaldehyde and its aqueous solution or hydrochloric acid as a solvent.

[0036] (3) Using a water-soluble lithium ion source (lithium chloride monohydrate) at normal pressure and 85° C., the polyvinyl alcohol colloid is preliminarily cross-linked to form a polyvinyl alcohol gel.

[0037] (4) Add 1% by weight of polyglycerol as a water-retaining agent to the preliminarily cross-linked polyvinyl alcohol glue.

[0038] (5) Add 1% by weight of potassium sorbate as an antibacterial agent to the preliminarily cross-linked polyvinyl alcohol glue.

[0039] (6) Add 1% by weight of a cosmetic emulsifier as an emulsifier to the preliminarily cross-linked polyvinyl alcohol glue.

[0040] (7) Add 0.5% by weight of natural flavor extract or edible flavor as a flavoring agent to the preliminarily cross-linked polyvinyl alcohol glue.

[0041] (8) Add 0.2% by weight of water-soluble food pigment as a colorant to the preliminarily cross-linked polyvinyl alcohol glue.

[0042] (9) The gel material is obtained by completely cross-linking the polyvinyl alcohol glue using a water-soluble potassium ion source (potassium chloride) at normal pressure and 70°C. If the polyvinyl alcohol glue does not form a gel, the gel material can be produced by vacuum distillation at 87°C, thereby forming a soft rubber toy with the thermally cross-linked gel material as the main body.

[0043] (10) After cooling the soft rubber toys made mainly of heat-crosslinked gel material to room temperature and performing vacuum defoaming, an appropriate amount of other solid toys or decorative particles that are compatible and compliant with the ingredients of such soft rubber toys may be added as fillers, and the toys may be divided into containers for sealing, labeling and packaging.

[0044] Preferably, the gel material formed by hydrogen bond thermal crosslinking of polyvinyl alcohol with lithium ions assisted by potassium ions in an aqueous phase is formed with non-toxic light metal ions such as lithium ions and potassium ions as the center and hydrogen bond crosslinking with polyvinyl alcohol as the skeleton, rather than ester bond crosslinking with polyacid as the skeleton.

[0045] Preferably, each step of the gel material and the hydrogen bond thermal cross-linking preparation process can be compatible with at least one or more components of the water retaining agent, antibacterial agent, emulsifier, flavoring agent, and colorant to form a soft rubber toy, and an appropriate amount of other solid toys or decorative particles that are compatible and compliant with the soft rubber toy ingredients can be added to the soft rubber toy as fillers.

[0046] Preferably, the gel material and the hydrogen bond thermal cross-linking preparation process and a scheme for preparing soft rubber toys based on the hydrogen bond thermal cross-linking gel material do not contain or involve sodium tetraborate (i.e. borax), formaldehyde and its aqueous solution and other migrating elements listed in the current national standard "GB6675: Toy Safety".

[0047] Preferably, the hydrogen bond thermal cross-linking preparation process of the gel material can be completely carried out through mechanical stirring in a reactor, and then released into a sterilized clean container through a liquid valve and subjected to vacuum defoaming, storage and transportation in batches. The temperature in the preparation process can achieve high-temperature sterilization of the raw materials, so it is easy to realize mechanical automation, clean and aseptic operations.

[0048] Preferably, the water-retaining agent polyglycerol used in the scheme for preparing soft rubber toys with the hydrogen-bonded thermally cross-linked gel material as the main body is a polyether rather than a polyol. This substance is not easy to cross-link with boric acid to form boric acid ester and has strong hydrophilicity, which can reduce the residual degree of toy components while retaining water and lubricating.

[0049] Preferably, the soft rubber toys obtained in the scheme of preparing soft rubber toys with the hydrogen bond thermal cross-linked gel material as the main body have good mechanical properties and can withstand high-intensity mechanical operations such as pulling and falling when the toys are reasonably abused; because it is a gel material with non-toxic light metal ions such as lithium ions and potassium ions as the center and hydrogen bond cross-linked with polyvinyl alcohol as the skeleton, it can self-repair the intramolecular damage caused by hydrogen bond breakage during water retention and static standing for several hours to several days after undergoing mechanical operation.

[0050] Preferably, the main material and other auxiliary additives and substances involved in the scheme of preparing soft rubber toys with the hydrogen bond thermal cross-linking gel material as the main body have no environmental hazards.

[0051] The gel material prepared by the present invention, which is centered on non-toxic light metal ions such as lithium ions and potassium ions and is cross-linked with polyvinyl alcohol by hydrogen bonds as a skeleton, has the remarkable advantages of not containing or involving toxic and harmful substances, having uniform components and little retention, having a simple preparation method and process, having a high degree of mechanical automation in the preparation process, having a high degree of cleanliness, having a low production cost, being energy-saving and efficient, being environmentally friendly, and being suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the hydrogen bond thermal crosslinking technology explained in the present invention, and a schematic diagram of the structure of a gel material formed by hydrogen bond thermal crosslinking of polyvinyl alcohol in an aqueous phase using lithium ions assisted by potassium ions.

[0053] Figure 2 This is a schematic diagram of the device in Example 1 and Example 2 of the present invention, wherein the heat source, the supporting instrument, and the stirring instrument are omitted, the reactor is represented by a three-necked round-bottom flask, and the reaction temperature is monitored by a thermometer. The figure is mainly for illustration, so there are no brands and parameters of the instruments and facilities.

[0054] Figure 3 This is an enlarged view of the local surface structure of the gel material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0055] The present invention is further described in detail below through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0056] The specific embodiments of the present invention provide a method for preparing the gel material formed by hydrogen-bond thermal crosslinking of polyvinyl alcohol in an aqueous phase with lithium ions assisted by potassium ions, and a method for preparing a soft rubber toy with the hydrogen-bond thermal crosslinked gel material as the main body.

[0057] The following are typical but non-limiting embodiments of the present invention:

[0058] Embodiment 1:

[0059] This embodiment provides a method for preparing a gel material formed by hydrogen-bonding thermal crosslinking of polyvinyl alcohol in an aqueous phase with lithium ions assisted by potassium ions, the method comprising the following steps:

[0060] (1) Weigh 50.0002 g of polyvinyl alcohol 1750±50 granules at 20°C and place them in a clean 24 / 29 standard port 500 ml four-necked single-layer cylindrical round-bottom glass reactor equipped with a mechanical stirrer (sealed with a 24 / 29 standard port polytetrafluoroethylene stirring plug), a 24 / 29 standard port 500 mm reflux condenser (connected to a 24 / 29 standard port 90° suction joint with a piston), a feeding port (connected to a 24 / 29 standard port 250 ml constant pressure dropping funnel for adding liquid materials; connected to a 24 / 29 standard port Φ75 mm triangular feeding funnel for adding solid materials) and a 24 / 29 standard port 200 mm thermometer sleeve, and set aside for later use. Use a thermocouple to monitor the internal reaction temperature.

[0061] (2) Weigh 400.0017 g of deionized water at 20° C. and add it to a reactor. Heat it to 92° C. and stir it at a constant temperature of 300 rpm with a mechanical stirrer for 2 h until the polyvinyl alcohol particles are dissolved to form a polyvinyl alcohol colloid. Continue stirring after the polyvinyl alcohol colloid is completely dissolved and keep it at 85° C. for later use.

[0062] (3) Weigh 40.0015 g of lithium chloride monohydrate solid particles at 20°C and add them into a reaction kettle. Stir at a constant temperature of 85°C until the lithium chloride monohydrate solid is completely dissolved to form a polyvinyl alcohol glue solution. Continue stirring for 3 minutes and keep the temperature at 70°C for later use. After the polyvinyl alcohol glue solution is cooled, a layer of partially cross-linked glue film may be formed on the surface.

[0063] (4) 40.0012 g of potassium chloride solid powder was weighed at 20° C. and added to a reaction kettle at 70° C. with a mechanical stirrer at 500 rpm to form the hydrogen bond thermal cross-linked gel material after it was completely dissolved and cross-linked.

[0064] Embodiment 2:

[0065] This embodiment provides a method for preparing a soft rubber toy with the hydrogen bond thermal cross-linking gel material as the main body, and the method comprises the following steps:

[0066] (1) Weigh 50.0016 g of polyvinyl alcohol 1750±50 granules at 20°C and place them in a clean 24 / 29 standard port 500 ml four-necked single-layer cylindrical round-bottom glass reactor equipped with a mechanical stirrer (sealed with a 24 / 29 standard port polytetrafluoroethylene stirring plug), a 24 / 29 standard port 500 mm reflux condenser (connected to a 24 / 29 standard port 90° suction joint with a piston), a feeding port (connected to a 24 / 29 standard port 250 ml constant pressure dropping funnel for adding liquid materials; connected to a 24 / 29 standard port Φ75 mm triangular feeding funnel for adding solid materials) and a 24 / 29 standard port 200 mm thermometer sleeve, and set aside for later use. Use a thermocouple to monitor the internal reaction temperature.

[0067] (2) Weigh 400.0004 g of deionized water at 20° C. and add it to a reactor. Heat it to 92° C. and stir it at a constant temperature of 300 rpm with a mechanical stirrer for 2 h until the polyvinyl alcohol particles are dissolved to form a polyvinyl alcohol colloid. Continue stirring after the polyvinyl alcohol colloid is completely dissolved and keep the temperature at 85° C. for later use.

[0068] (3) Weigh 40.0033 g of lithium chloride monohydrate solid particles at 20°C and add them into a reaction kettle. Stir at a constant temperature of 85°C until the lithium chloride monohydrate solid is completely dissolved to form a polyvinyl alcohol glue solution. Continue stirring for 3 minutes and keep the temperature at 70°C for later use. After the glue solution is cooled, a layer of partially cross-linked glue film may be formed on the surface.

[0069] (4) At 20°C, weigh 5.3013g of decaglycerol, 5.3001g of potassium sorbate, 5.3028g of Span-80 (also known as Span-80, i.e., emulsifier S-80), 2.6504g of D-limonene (source: orange peel extract), and 1.0601g of hydrazine yellow (also known as lemon yellow, i.e., food additive acid yellow 23), add them into a reaction kettle at 70°C, and stir at a constant temperature of 400rpm for 5 minutes with a mechanical stirrer to completely dissolve all the additives and evenly disperse them in the polyvinyl alcohol glue solution. Continue stirring for 3 minutes and keep the temperature at 70°C for later use. After the glue solution is cooled, a layer of partially cross-linked glue film can be formed on the surface.

[0070] (5) Weigh 40.0010 g of potassium chloride solid powder at 20° C., add it to a reactor at 70° C. while stirring it at 500 rpm with a mechanical stirrer, and wait until it is completely dissolved and cross-linked to form a soft rubber toy with hydrogen bond thermal cross-linking gel material as the main body.

[0071] (6) After the formed soft rubber toy with hydrogen bond thermal cross-linking gel material as the main body is cooled to room temperature, it is divided into four clean 100 ml non-porous plastic packaging boxes, placed in a Φ240 mm vacuum dryer with an open mouth and defoamed under low vacuum for 5 minutes. The packaging box is sealed and labeled, and the preparation process of the soft rubber toy is completed. It can then be stored and transported.

[0072] The reagent material parameters selected in Examples 1 and 2 of the present invention are: polyvinyl alcohol 1750±50-Shanghai Sinopharm Group-99%; deionized water-self-made in the laboratory; lithium chloride monohydrate-Shanghai Sinopharm Group-analytical grade AR; potassium chloride-Shanghai Sinopharm Group-superior grade GR; decaglycerol-McLean's reagent-98%; potassium sorbate-Shanghai Sinopharm Group-chemically pure CP; Span-80 (also known as Span-80, i.e. emulsifier S-80)-Shanghai Sinopharm Group-chemically pure CP; D-limonene (source: orange peel extract)-McLean's reagent-95%; hydrazine yellow (also known as lemon yellow, i.e. food additive acid yellow 23)-Shanghai Sinopharm Group-BS.

[0073] The gel material prepared by the present invention, which is centered on non-toxic light metal ions such as lithium ions and potassium ions and is cross-linked with polyvinyl alcohol by hydrogen bonds as a skeleton, has the remarkable advantages of not containing or involving toxic and harmful substances, having uniform components and little retention, having a simple preparation method and process, having a high degree of mechanical automation in the preparation process, having a high degree of cleanliness, having a low production cost, being energy-saving and efficient, being environmentally friendly, and being suitable for industrial production.

[0074] The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hydrogen bond thermal crosslinking preparation process for a hydrophilic gel material centered on non-toxic light metal ions and based on hydrogen bond crosslinking as a skeleton, characterized in that: The main components of the gel are calculated by mass percentage, including: deionized water 60%-75.5%; polyvinyl alcohol 1750±50 9%-15%; lithium chloride monohydrate 7.5%-10%; potassium chloride 5%-7.5%; The process comprises the following steps: (1) dissolving polyvinyl alcohol in deionized water at a temperature between 70° C. and 95° C. under normal pressure to form polyvinyl alcohol colloid; (2) using lithium chloride monohydrate to preliminarily cross-link the polyvinyl alcohol colloid to form a polyvinyl alcohol glue solution at a temperature between 80° C. and 90° C. under normal pressure; (3) Using potassium chloride to completely cross-link the polyvinyl alcohol glue at a temperature between 60°C and 80°C under normal pressure to obtain the gel material.

2. The preparation process according to claim 1, characterized in that: The process comprises the following steps: (1) dissolving polyvinyl alcohol in deionized water at normal pressure and 92° C. to form polyvinyl alcohol colloid; (2) using lithium chloride monohydrate to preliminarily cross-link the polyvinyl alcohol colloid at normal pressure and a temperature of 85° C. to form a polyvinyl alcohol colloid; (3) The polyvinyl alcohol gel was completely cross-linked using potassium chloride at normal pressure and 70°C to obtain the gel material.

3. A hydrophilic gel material with non-toxic light metal ions as the center and hydrogen bond cross-linking as the skeleton, prepared by the preparation process as claimed in claim 1 or claim 2.

4. A process for preparing soft plastic toys with a hydrophilic gel material centered on non-toxic light metal ions and with hydrogen bond cross-linking as the skeleton as the main body, characterized in that: The main components of the gel are calculated by mass percentage, including: deionized water 60%-75.5%; polyvinyl alcohol 1750±50 9%-15%; lithium chloride monohydrate 7.5%-10%; potassium chloride 5%-7.5%; The process comprises the following steps: (1) Calculate and obtain the required deionized water, polyvinyl alcohol 1750±50, lithium chloride monohydrate, potassium chloride, water retaining agent, antibacterial agent, emulsifier, flavoring agent, and coloring agent in advance according to the mass percentage of the main components of the gel; (2) dissolving polyvinyl alcohol in deionized water at normal pressure and 92° C. to form polyvinyl alcohol colloid; (3) using lithium chloride monohydrate to preliminarily cross-link the polyvinyl alcohol colloid at normal pressure and a temperature of 85° C. to form a polyvinyl alcohol colloid; (4) adding 1% by weight of polyglycerol as a water retaining agent to the preliminarily cross-linked polyvinyl alcohol glue; (5) adding 1% by weight of potassium sorbate as an antibacterial agent to the preliminarily cross-linked polyvinyl alcohol glue; (6) adding 1% by weight of a cosmetic emulsifier as an emulsifier to the preliminarily cross-linked polyvinyl alcohol glue; (7) adding 0.5% by weight of natural flavor extract or edible flavor as a flavoring agent to the preliminarily cross-linked polyvinyl alcohol glue; (8) adding 0.2% by weight of a water-soluble food pigment as a colorant to the preliminarily cross-linked polyvinyl alcohol glue; (9) using potassium chloride to completely cross-link the polyvinyl alcohol glue at normal pressure and 70° C. to obtain the gel material; (10) After the soft rubber toy is cooled to room temperature and vacuum defoamed, other solid toys or decorative particles that are compatible with the ingredients of the soft rubber toy and comply with regulations are added as fillers, and the soft rubber toy is divided into containers for sealing, labeling and packaging.

5. A soft rubber toy with a hydrophilic gel material as the main body and a non-toxic light metal ion as the center and a hydrogen bond cross-linking as the skeleton, obtained by the preparation process as described in claim 4.

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