Biodegradable glue and preparation method thereof

Abstract

The preparation method comprises the following steps: S1, carrying out ring opening polymerization on a bio-based material a and an initiator under the action of a catalyst to prepare bio-based polyol; s2, reacting the bio-based polyol obtained in the step S1 with carboxylic acid unsaturated ester to obtain a polyester copolymer containing unsaturated double bonds; and S3, under the action of an initiator, carrying out a free radical polymer reaction on the polyester copolymer containing the unsaturated double bonds obtained in S2 and a vinyl monomer to obtain the biodegradable hot-melt pressure-sensitive adhesive. Aiming at the problems of low initial adhesion and poor aging resistance in the existing biodegradable adhesive, the biomass monomer of the biodegradable adhesive is modified, the stability of the raw materials is improved, and the adhesion of the adhesive is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of biodegradable glue preparation, and in particular to a biodegradable glue and a preparation method thereof. Background Art

[0002] Traditional adhesives are derived from petroleum products and cannot be degraded after use, resulting in a large amount of waste. With the increasing consumption of petroleum resources, renewable resources have replaced some petroleum-based materials, and more and more research has been conducted on biodegradable adhesive resins. The synthesis method of degradable hot melt pressure-sensitive adhesive can be discussed from two aspects. On the one hand, it is synthesized using natural degradable materials. On the other hand, it is synthesized using artificially synthesized degradable polymers. Artificially synthesized degradable polymers synthesize hot melt pressure-sensitive adhesives by using synthetic degradable polyols or degradable diisocyanates to partially or completely replace the non-degradable raw materials used in the synthesis of polyurethane, thereby synthesizing degradable adhesives.

[0003] Bio-based monomers are derived from renewable resources, have good biodegradability, contain hydroxyl and carboxyl groups in their molecular structure, are easily converted into ester monomers, and have good biocompatibility. However, since the polycondensation reaction of bio-based monomers is a reversible reaction, there is a balance of lactic acid, water, lactic acid oligomers and lactide in the system, and it is not easy to obtain high molecular weight polymers by direct methods. In actual operation, the small molecule water produced by melt polycondensation is difficult to remove, and the occurrence of side reactions is inevitable, resulting in the inability of bio-based monomers and oligomers to reach the required molecular weight. For example: CN107418501A reported the use of plant oil-based polyols to prepare biodegradable adhesives, but the initial adhesion and holding force of the prepared adhesives were not high enough, especially when used at low temperatures. CN103694941A reported a high solid content water-based polyurethane adhesive prepared from polyester / polyether polyols and polyisocyanates, using acetone as a solvent, with high production costs, which is not conducive to industrial production. Chinese patent publication number CN1288033A discloses a method for preparing a water-soluble biodegradable adhesive from a mixture of polyaspartic acid, its salts and derivatives and a natural thickener resin. The method is complex and costly, and the prepared adhesive has poor water resistance, poor viscosity and is not solvent-resistant. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a biodegradable adhesive and a preparation method thereof. In view of the problems of low initial adhesion and poor anti-aging performance existing in existing biodegradable adhesives, the biomass monomers of the biodegradable adhesive are modified to improve the stability of the raw materials and further improve the adhesion of the adhesive.

[0005] In order to solve the above technical problems, the present invention provides a biodegradable adhesive and a preparation method thereof, comprising the following steps: S1, subjecting a bio-based material a and an initiator to ring-opening polymerization under the action of a catalyst to prepare a bio-based polyol; S2, reacting the bio-based polyol obtained in S1 with an unsaturated ester of a carboxylic acid to obtain a polyester copolymer containing unsaturated double bonds; S3, subjecting the polyester copolymer containing unsaturated double bonds obtained in S2 to a free radical polymerization reaction with a vinyl monomer under the action of an initiator to obtain a biodegradable hot-melt pressure-sensitive adhesive.

[0006] Furthermore, the initiator in step S1 is a polyol.

[0007] Furthermore, the specific reaction process of step S1 is as follows: A1: Bio-based material a and initiator, nitrogen replacement, oil temperature set at 100-120℃ to heat up and melt clearly, water pump at 110-120℃ to decompress and dehydrate for 1h; A2: Add catalyst under nitrogen environment, continue to heat to 140-160℃ for 20h, remove light components by water pump under reduced pressure for 1.5h, and then cool to 60-80℃; A3: Pour into a special small bucket and continue to cool to room temperature and store for 8 hours to obtain bio-based polyol.

[0008] Further, in step S1: The feed ratio of bio-based material a to initiator is: 8:(2-4); The initiator is one of BDO, TMP, NPG and DEG; The catalyst is one of dibutyltin dilaurate, di(dodecylsulfide) dibutyltin, stannous octoate, dibutyltin diacetate, and triphenyltin, and the mass of the catalyst is 0.5% of the total mass of the substrate.

[0009] Furthermore, the specific reaction process of step S2 is as follows: Unsaturated esters of bio-based polyols and carboxylic acids, nitrogen replacement, setting the oil temperature at 130-160°C to heat and melt clearly, adding catalysts under nitrogen environment, decompression and dehydration reaction for 6-24 hours, to obtain polyester copolymers containing unsaturated double bonds; The unsaturated ester of carboxylic acid is one of oleic acid, linolenic acid, α-linolenic acid, acrylic acid and itaconic acid, and the catalyst is 0.5% of the total mass of the substrate; The feed ratio between bio-based polyol and unsaturated ester of carboxylic acid is (7-9): (1-3).

[0010] Furthermore, the specific reaction process of step S3 is as follows: Polyester copolymers containing unsaturated double bonds and vinyl monomers are replaced with nitrogen, the oil temperature is set at 160-200°C, an initiator (0.1-5wt% of the vinyl monomer) is added under nitrogen environment, and the reaction is carried out for 4-20 hours to obtain a biodegradable hot melt adhesive.

[0011] The beneficial effects of the present invention are as follows: 1. The method has a simple process and can obtain a high molecular weight biodegradable adhesive with a biodegradation rate of ≥90%.

[0012] 2. The prepared adhesive has high stability and can effectively extend the service life of the product.

[0013] 3. The process of this method is environmentally friendly and pollution-free, and no three wastes are discharged, which is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the reaction flow chart of step S1 of the present invention Figure 2 It is a reaction flow chart of steps S2 and S3 of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0016] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0017] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0021] Reference Figure 1 to Figure 2 As shown, an embodiment of a biodegradable adhesive and a preparation method thereof of the present invention comprises the following steps: S1, subjecting a bio-based material a and an initiator to ring-opening polymerization under the action of a catalyst, wherein the initiator is a polyol, to prepare a bio-based polyol; S2, reacting the bio-based polyol obtained in S1 with an unsaturated ester of a carboxylic acid to obtain a polyester copolymer containing unsaturated double bonds; S3, subjecting the polyester copolymer containing unsaturated double bonds obtained in S2 to a free radical polymerization reaction with a vinyl monomer under the action of an initiator to obtain a biodegradable hot-melt pressure-sensitive adhesive.

[0022] The specific reaction process of step S1 is as follows: A1: Bio-based material a and initiator, nitrogen replacement, oil temperature set at 100-120℃ to heat up and melt clearly, water pump at 110-120℃ to decompress and dehydrate for 1h; A2: Add catalyst under nitrogen environment, continue to heat to 140-160℃ for 20h, remove light components by water pump under reduced pressure for 1.5h, and then cool to 60-80℃; A3: Pour into a special small bucket and continue to cool to room temperature and store for 8 hours to obtain bio-based polyol.

[0023] Wherein in step S1: The feed ratio of bio-based material a to initiator is: 8:(2-4); The initiator is one of BDO, TMP, NPG and DEG; The catalyst is one of dibutyltin dilaurate, di(dodecylsulfide) dibutyltin, stannous octoate, dibutyltin diacetate, and triphenyltin, and the mass of the catalyst is 0.5% of the total mass of the substrate. At this time, the purity of the bio-based polyol produced in step S1 is ≥95%.

[0024] The specific reaction process of step S2 is as follows: Bio-based polyols and unsaturated esters of carboxylic acids, nitrogen replacement, set the oil temperature to 130-160℃ to heat up and melt clearly, add catalyst under nitrogen environment, decompress and dehydrate for 6-24h to obtain polyester copolymers containing unsaturated double bonds, and the bio-based polyols and unsaturated double bond polyester copolymers must be continuously dehydrated during the reaction to ensure the reaction proceeds in the forward direction; The unsaturated ester of carboxylic acid is one of oleic acid, linolenic acid, α-linolenic acid, acrylic acid and itaconic acid, and the catalyst is 0.5% of the total mass of the substrate; The feed ratio between bio-based polyol and unsaturated ester of carboxylic acid is (7-9): (1-3).

[0025] The specific reaction process of step S3 is as follows: Polyester copolymers containing unsaturated double bonds and vinyl monomers are replaced with nitrogen, the oil temperature is set at 160-200°C, an initiator (0.1-5wt% of the vinyl monomer) is added under nitrogen environment, and the reaction is carried out for 4-20 hours to obtain a biodegradable hot melt adhesive.

[0026] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A biodegradable glue and a preparation method thereof, characterized in that: The steps include: S1, performing ring-opening polymerization on a bio-based material a and an initiator under the action of a catalyst to prepare a bio-based polyol; S2, reacting the bio-based polyol obtained in S1 with an unsaturated ester of a carboxylic acid to obtain a polyester copolymer containing an unsaturated double bond; S3. Under the action of an initiator, the polyester copolymer containing unsaturated double bonds obtained in S2 and a vinyl monomer are subjected to a free radical polymerization reaction to obtain a biodegradable hot melt pressure-sensitive adhesive.

2. The biodegradable glue and preparation method thereof according to claim 1, characterized in that: The initiator in step S1 is polyol.

3. The biodegradable glue and preparation method thereof according to claim 1, characterized in that: The specific reaction process of step S1 is as follows: A1: Bio-based material a and initiator, nitrogen replacement, oil temperature set at 100-120℃ to heat up and melt clearly, water pump at 110-120℃ to decompress and dehydrate for 1h; A2: Add catalyst under nitrogen environment, continue to heat to 140-160℃ for 20h, remove light components by water pump under reduced pressure for 1.5h, and then cool to 60-80℃; A3: Pour into a special small bucket and continue to cool to room temperature and store for 8 hours to obtain bio-based polyol.

4. The biodegradable glue and the preparation method thereof according to claim 3, characterized in that: In the step S1: The feed ratio of bio-based material a to initiator is: 8:(2-4); The initiator is one of BDO, TMP, NPG and DEG; The catalyst is one of dibutyltin dilaurate, di(dodecylsulfide) dibutyltin, stannous octoate, dibutyltin diacetate, and triphenyltin, and the mass of the catalyst is 0.5% of the total mass of the substrate.

5. The biodegradable glue and the preparation method thereof according to claim 1, characterized in that: The specific reaction process of step S2 is as follows: Unsaturated esters of bio-based polyols and carboxylic acids, nitrogen replacement, setting the oil temperature at 130-160°C to heat and melt clearly, adding catalysts under nitrogen environment, decompression and dehydration reaction for 6-24 hours, to obtain polyester copolymers containing unsaturated double bonds; The unsaturated ester of carboxylic acid is one of oleic acid, linolenic acid, α-linolenic acid, acrylic acid and itaconic acid, and the catalyst is 0.5% of the total mass of the substrate; The feed ratio between bio-based polyol and unsaturated ester of carboxylic acid is (7-9): (1-3).

6. The biodegradable glue and the preparation method thereof according to claim 1, characterized in that: The specific reaction process of step S3 is as follows: Polyester copolymers containing unsaturated double bonds and vinyl monomers are replaced with nitrogen, the oil temperature is set at 160-200°C, an initiator (0.1-5wt% of the vinyl monomer) is added under nitrogen environment, and the reaction is carried out for 4-20 hours to obtain a biodegradable hot melt adhesive.

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