阅读说明：本技术 一种生物基交联可回收聚氨酯组合料及其制备方法 (Bio-based cross-linked recyclable polyurethane composite material and preparation method thereof ) 是由 巴龙翰 高彦升 王凯 于 2020-07-10 设计创作，主要内容包括：本发明公开了一种生物基交联可回收聚氨酯组合料及其制备方法,所述生物基交联可回收聚氨酯组合料包括：含有双烯烃结构的聚氨酯预聚体,和一种生物基改性聚酯交联剂,本发明的聚氨酯材料是通过双烯加成反应实现固化,并通过温度刺激实现化合键的正向-可逆反应,实现110-130℃可流动不固化,在60-70℃固化,加热可回收再利用。(The invention discloses a bio-based crosslinking recyclable polyurethane composite material and a preparation method thereof, wherein the bio-based crosslinking recyclable polyurethane composite material comprises the following components: the polyurethane material realizes curing through diene addition reaction, realizes forward-reversible reaction of chemical bonds through temperature stimulation, realizes flowable non-curing at 110-130 ℃, cures at 60-70 ℃, and can be recycled through heating.)

1. A bio-based cross-linked recyclable polyurethane composite material, characterized in that the composite material at least comprises the following components:

the component A comprises: polyurethane prepolymer containing diolefin structure

And B component: a bio-based modified polyester cross-linking agent;

wherein, the bio-based modified polyester cross-linking agent is obtained by the reaction of itaconic acid and polycaprolactone terminated by single and double bonds.

2. The polyurethane composition according to claim 1, wherein the polyurethane prepolymer containing diolefin structure is prepared by reacting diisocyanate, polyester and/or polyether polyol, and furan amine.

3. The polyurethane composition according to claim 1 or 2, wherein the diene-structure-containing polyurethane prepolymer is prepared by mixing diisocyanate, polyether and/or polyester polyol, and furan amine in a molar ratio of 2: 2: 1-1.2, stirring and reacting for 2-4 hours at 70-80 ℃.

4. A polyurethane package according to claim 2 or 3, characterized in that said diisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate and liquefied MDI, preferably from one or more of toluene diisocyanate, diphenylmethane diisocyanate and liquefied MDI; and/or:

the polyether polyol is polyoxyethylene polyol and/or polytetrahydrofuran polyol, preferably, the molecular weight of the polyether polyol is 500-2500, and further preferably 600-2000; and/or:

the polyester polyol is one or more of polybutylene adipate glycol polyester polyol, polycarbonate polyol and poly-caprolactone polyol, preferably, the molecular weight of the polyester polyol is 500-2500, and further preferably 600-2000; and/or:

the furan amine is selected from furan methylamine and furan ethylamine.

5. The polyurethane composition according to claim 1, wherein the structure of the single-double bond terminated polycaprolactone is as follows:

wherein R is selected from hydrogen and methyl; n is 1 to 4.

6. The polyurethane composition according to claim 1 or 5, wherein the bio-based modified polyester cross-linking agent is itaconic acid and a mono-or di-bond terminated polycaprolactone at a molar ratio of 1-1.1: 2 is obtained by reaction.

7. The polyurethane composition according to any one of claims 1 to 6, wherein the molar ratio of the A component to the B component is 1 to 1.2: 1.

8. the polyurethane composition according to any one of claims 1-7, wherein the component A and the component B are heated at 110-130 ℃ and then mixed according to a molar ratio of 1-1.2: 1, or mixing the component A and the component B according to a molar ratio of 1-1.2: 1 heating at 110-130 ℃ after mixing; stirring uniformly, and curing at 60-70 ℃ for 16-20 hours to obtain the recyclable polyurethane.

9. The polyurethane composition according to any one of claims 1 to 8, further optionally comprising one or more of an internal mold release agent, a flame retardant, a pigment, an antistatic agent, an antioxidant, a UV stabilizer, a defoamer, a coupling agent, a leveling agent, a water scavenger, a molecular sieve, a thixotropic agent, a filler and a plasticizer.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to a polyurethane composite material which is flowable at high temperature, is cured at 70 ℃ and can be recycled through bio-based crosslinking and a preparation method thereof.

Background

The polyurethane as a polymer material can be used for preparing products with different performance requirements, and has excellent toughness, impact resistance, wear resistance and tear resistance. The polyurethane processing and forming process is simple, can adopt one-time injection molding and one-time casting molding, and can realize different curing processes and performances through formula design.

Because the reactivity of the isocyanate component of the polyurethane resin is too high, once the isocyanate component is uniformly mixed with the polyol or polyamine component, the polyurethane resin can be gelled and solidified within a few seconds to a few hours, so that the fluidity of the polyurethane is lost, the process operation cannot be carried out, and the application of the polyurethane is limited to a certain extent. In addition, the chemical industry nowadays not only requires products with excellent comprehensive properties, but also has safe, green and environment-friendly production process, and is a development trend. The development and utilization of renewable resources have become an important research direction in modern chemical industry.

Therefore, aiming at the problems and development trends faced by the industry at present, the invention develops a suitable polyurethane composite material which has long operable time and can be recycled and reused by utilizing bio-based raw materials through a non-traditional curing mode.

Disclosure of Invention

The invention aims to expand the application field of polyurethane materials and provides a bio-based crosslinking recyclable polyurethane composite material and a preparation method thereof, wherein the composite material adopts a reversible non-traditional crosslinking mode, can flow at high temperature for a long time and has proper operation time; adopts bio-based raw materials, and can be recycled. Can be mixed with the traditional polyurethane according to different product requirements to play a role in reinforcement.

By operating time is meant the time the composition does not harden and remains sufficiently fluid relative to its use (e.g., injection molding, RTM, thermal bonding).

In order to achieve the above objects and achieve the above technical effects, the technical solution of the present invention is as follows:

a bio-based cross-linked recyclable polyurethane composite, the composite comprising at least the following components:

the component A comprises: polyurethane prepolymer containing diolefin structure

And B component: a bio-based modified polyester cross-linking agent.

In the invention, the polyurethane prepolymer containing a diolefin structure (furan ring) is prepared by the polymerization reaction of diisocyanate, polyester and/or polyether polyol and furan amine;

wherein the diisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate and liquefied MDI, preferably from one or more of toluene diisocyanate, diphenylmethane diisocyanate and liquefied MDI;

wherein the polyether polyol is polyoxyethylene polyol and/or polytetrahydrofuran polyol, and the molecular weight is 500-2500, preferably 600-2000;

wherein the polyester polyol is one or more of poly-adipate butanediol glycol polyester polyol, polycarbonate polyol and poly-caprolactone polyol, and has a molecular weight of 500-2500, preferably 600-2000;

wherein, the structural formula of the furan amine is as follows:

preferably furanmethanamine and/or furanethylamine.

In the invention, the polyurethane prepolymer containing a diolefin structure is prepared by mixing isocyanate, polyether and/or polyester polyol and furan amine according to a molar ratio of 2: 2: 1-1.2, stirring and reacting for 2-4 hours at 70-80 ℃.

In the invention, the bio-based modified polyester cross-linking agent is prepared by esterification polymerization reaction of itaconic acid and polycaprolactone terminated by single and double bonds.

Wherein the polycaprolactone terminated by single double bond is a low molecular polymer containing double bonds and hydroxyl, the molecular weight is 200-2000, preferably 210-1000, and the structural formula is as follows:

wherein R is selected from hydrogen and methyl; n is 1 to 4.

Wherein, the itaconic acid is a biological base material, and the structural formula is as follows:

in the invention, the bio-based modified polyester crosslinking agent is prepared by mixing itaconic acid and single-double bond terminated polycaprolactone according to a molar ratio of 1-1.1: 2, adding a catalyst such as concentrated sulfuric acid accounting for about 0.1-0.2 percent of the total mass of the raw materials, stirring and reacting at the temperature of 100 ℃ and 110 ℃ for 4-5 hours, and dehydrating to obtain the catalyst.

In the invention, the component A and the component B can be respectively heated at the temperature of 110-130 ℃, and then the components are mixed according to the molar ratio of 1-1.2: 1, or mixing the component A and the component B according to a molar ratio of 1-1.2: 1 heating at 110-130 ℃ after mixing; stirring evenly, and then curing for 16-20 hours at 60-70 ℃ to obtain the bio-based crosslinking recoverable polyurethane. Double bonds are introduced into a polyurethane system through the component A and the component B, the material preparation is based on diene addition reaction to realize crosslinking, the reaction is reversible reaction with temperature response, the reaction is forward reaction at 60-70 ℃ to form a cyclohexane structure, polyurethane crosslinking and curing are realized, the reaction is reverse reaction at 110-130 ℃, the covalent bond is broken, polyurethane degradation is realized, and based on the mechanism, the polyurethane composition material can realize long-time flow non-solidification at about 120 ℃ and curing reaction at about 70 ℃ through temperature stimulation. The polyurethane prepared by the invention can be heated and reprocessed after being crushed, or can be dissolved in a solvent at about 120 ℃ for recycling, so that the polyurethane can be recycled.

According to the invention, different additives can be added according to different product requirements, and comprise one or more of an internal release agent, a flame retardant, a pigment, an antistatic agent, an antioxidant, a UV stabilizer, a defoaming agent, a coupling agent, a leveling agent, a water removing agent, a molecular sieve, a thixotropic agent and a plasticizer. Fillers, including inorganic fillers, may also be added to the present invention as desired: siliceous minerals such as antigorite, bentonite, serpentine, amphibole, chrysotile and talc; metal oxides such as kaolin, alumina, titanium oxide, zinc oxide and iron oxide; metal salts, such as chalk and barite; and glass and the like. Possible organic fillers are, for example: carbon black, melamine, rosin, cyclopentadiene resins and graft polymers, and also cellulose fibers, polyamides, polyacrylonitriles, polyester fibers based on aromatic and/or aliphatic dicarboxylic acid esters, and in particular carbon fibers.

The polyurethane composite material can be applied to hot press molding, casting molding, injection compression molding, flow molding, Reaction Injection Molding (RIM), RTM (resin transfer molding), VARTM (vacuum assisted RTM), blending extrusion hot-pressing molding, blending extrusion re-casting molding and the like.

The invention has the positive effects that:

(1) the composite material is applied to renewable bio-based raw materials, is green and environment-friendly, has sufficient production operation time, and can be used for large workpiece products and composite materials needing to be soaked in fibers for a long time.

(2) The polyurethane material prepared by the composite material can be recycled, and the broken polyurethane material can be heated and reprocessed for reuse, so that non-renewable petroleum resources are greatly reduced.

(3) The invention prepares a polyurethane prepolymer and a cross-linking agent, provides a novel polyurethane cross-linking mode, is different from the prior polyurethane curing, prepares a polyurethane prepolymer with a furan ring as a side group, and forms a cross-linking curing network by reacting with the cross-linking agent with double bonds, which is different from the prior polyurethane micromolecule chain extension reaction. The cross-linking agent is prepared by reacting a monomer containing a polycaprolactone structure with itaconic acid, so that the cured polyurethane material still retains the characteristic of polyurethane flexibility. In addition, the forward-reversible reaction of chemical bonds is realized through temperature stimulation, and the polyurethane functionalization is realized by using the temperature as a switch.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are further described. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical scheme of the invention is further explained by combining the embodiment.

And (3) tensile test: GB/T2567-2008, Zwick Z005 testing machine, the testing temperature is 23 +/-2 ℃, and the testing speed is 500 mm/min.

The raw materials used in the comparative examples and examples of the present invention are described below:

FA 1: acrylate polycaprolactone having a molecular weight of 230, single and double bond end-capped, Daiiluo Co Ltd

FA 2D: acrylate polycaprolactone having a molecular weight of 344, single and double bond end-capped, Daiiluo Co., Ltd

FM 1: 244 molecular weight, single and double bond terminated methacrylate polycaprolactone, Daiiluo Co Ltd

FM 2D: mono-and di-bond terminated methacrylate polycaprolactone having a molecular weight of 358, Daiiluo Co

TDI-100: NCO content 48.2 wt.%, diisocyanate, Vanhua chemical group Ltd

MDI-50: NCO content 33.5 wt.%, diisocyanate, Furanethylamine, Vanhua Chemicals group Ltd: aladdin

PEG 600: molecular weight 600, Dow chemical

PCL 210N: molecular weight 1000, xylonite

PTMEG-650: molecular weight 650, basf

Hydroxypropyl methacrylate, Aladdin

Itaconic acid: hibiscus rosa-sinensis

Comparative example 1

Preparing a furan ring-terminated polyurethane prepolymer:

MDI-50 and PCL210N are mixed according to a molar ratio of 2: 1, feeding materials, and stirring and reacting for 3 hours at 75 ℃ to prepare an isocyanate-terminated polyurethane prepolymer;

and (3) mixing furan ethylamine with the prepolymer according to a molar ratio of 2: 1, feeding materials, and stirring and reacting for 2 hours at 70 ℃ to prepare a furan ring-terminated polyurethane prepolymer;

preparing a cross-linking agent: itaconic acid and hydroxypropyl methacrylate are mixed according to a molar ratio of 1: 2, feeding, adding concentrated sulfuric acid with the total mass of 0.1%, reacting for 5 hours at 100 ℃, and then distilling and dehydrating to obtain the catalyst;

and (2) mixing the furan ring-terminated polyurethane prepolymer and a cross-linking agent at 110 ℃ according to a molar ratio of 1: 1, heating and mixing, stirring uniformly, curing for 20 hours at 70 ℃ to obtain the polyurethane of the comparative example, and the test performance is shown in Table 1.