阅读说明：本技术 一种汽车方向盘用自结皮聚氨酯泡沫快速脱模组合物及其制备方法 (Self-skinning polyurethane foam rapid demoulding composition for automobile steering wheel and preparation method thereof ) 是由 张利国 赵修文 李博 张莉 张涛 赵卫鸣 于 2020-04-15 设计创作，主要内容包括：本发明公开了一种汽车方向盘用自结皮聚氨酯泡沫快速脱模组合物及其制备方法,组合物A组分包括聚醚多元醇、聚合物多元醇、纳米改性离型剂、扩链剂、催化剂、泡沫稳定剂、发泡剂、开孔剂,B组分为异氰酸根含量为23％-31wt％的改性全MDI体系异氰酸酯预聚体。所述纳米改性离型剂由以下方法制备：(1)将纳米碳酸钙分散在甲苯中,加入γ-异氰酸丙基三乙氧基硅烷,70-120℃回流6-8h,离心,洗涤,真空干燥获取改性纳米碳酸钙；(2)将改性纳米碳酸钙与蓖麻油多元醇按照1/1-1/2的质量比混合研磨,然后升温到70-90℃搅拌反应1.5-3h,降温到15-25℃与稀释剂按照1/2-2/1的质量比混合均匀,即可制得纳米改性离型剂；所述的稀释剂为碳原子大于等于8的芳烃油、环烷油或链烷烃油。(The invention discloses a self-skinning polyurethane foam rapid demoulding composition for an automobile steering wheel and a preparation method thereof, wherein a component A of the composition comprises polyether polyol, polymer polyol, a nano modified release agent, a chain extender, a catalyst, a foam stabilizer, a foaming agent and a pore opening agent, and a component B of the composition is a modified full MDI system isocyanate prepolymer with the content of isocyanic acid radical of 23-31 wt%. The nano modified release agent is prepared by the following method: (1) dispersing nano calcium carbonate in toluene, adding gamma-isocyanatopropyl triethoxysilane, refluxing for 6-8h at 70-120 ℃, centrifuging, washing, and drying in vacuum to obtain modified nano calcium carbonate; (2) mixing and grinding modified nano calcium carbonate and castor oil polyhydric alcohol according to the mass ratio of 1/1-1/2, then heating to 70-90 ℃, stirring and reacting for 1.5-3h, cooling to 15-25 ℃, and uniformly mixing with a diluent according to the mass ratio of 1/2-2/1 to obtain a nano modified release agent; the diluent is aromatic oil, naphthenic oil or paraffinic oil with carbon atoms more than or equal to 8.)

1. A self-skinning polyurethane foam rapid demoulding composition for an automobile steering wheel comprises A, B two components in parts by mass:

the component A comprises:

and B component: a modified full MDI system isocyanate prepolymer with isocyanate content of 23-31 wt%;

the polyether polyol 1 is high-activity polyether polyol which is initiated by glycerol, has the three-functionality degree, the molecular weight of 3000-10000 and the content of terminal primary hydroxyl groups of more than 70 percent;

the nano modified release agent is prepared by the following method: (1) dispersing nano calcium carbonate in toluene, adding gamma-isocyanatopropyl triethoxysilane, refluxing for 6-8h at 70-120 ℃, centrifuging, washing, and drying in vacuum to obtain modified nano calcium carbonate; (2) mixing and grinding modified nano calcium carbonate and castor oil polyhydric alcohol according to the mass ratio of 1/1-1/2, then heating to 70-90 ℃, stirring and reacting for 1.5-3h, cooling to 15-25 ℃, and uniformly mixing with a diluent according to the mass ratio of 1/2-2/1 to obtain a nano modified release agent; the diluent is aromatic oil, naphthenic oil or paraffinic oil with carbon atoms more than or equal to 8.

2. The composition according to claim 1, wherein the polymer polyol is a trifunctional, 25-45% solids, styrene-acrylonitrile grafted high activity polymer polyol.

3. The self-skinning polyurethane foam rapid release composition for an automobile steering wheel according to claim 1, wherein the chain extender is at least one selected from the group consisting of: ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, or diethylene glycol; the catalyst refers to organometallic catalysts and amine catalysts.

4. The self-skinning polyurethane foam rapid release composition for automobile steering wheels according to claim 3, wherein the organometallic catalyst is dibutyltin dilaurate (T12), stannous octoate (T12), dibutyltin diacetate or dibutyltin bis (dodecylthio).

5. The self-skinning polyurethane foam rapid release composition for automobile steering wheels according to claim 4, wherein the amine catalyst is a dipropylene glycol solution (A) having a bis (dimethylaminoethyl) ether content of 70%₁) Dipropylene glycol solution (A) containing 33% of triethylenediamine₃₃) Dimethylethanolamine (DMEA), Pentamethyldiethylenetriamine (PMDETA), Tetramethylethylenediamine (TMEDA) or Dimethylaminoethoxyethanol (DMAEE).

6. The self-skinning polyurethane foam rapid release composition for automobile steering wheels according to claim 1 wherein the full MDI system isocyanate is a mixture of diphenylmethane diisocyanate (MDI) monomer, urethane-modified MDI, carbodiimide-modified MDI, and has a functionality of 2.0 to 2.7.

7. The self-skinning polyurethane foam rapid release composition for an automobile steering wheel according to claim 1, wherein the blowing agent of the present invention is water; the foam stabilizer is B8715 and B8736 of Germany winning and creating industry group, DC2525 and DC6070 of American gas and chemical company, and L-3629 and L-3640 of American Mitigo high-new material group; the cell opener is a high Ethylene Oxide (EO) content polyether polyol, wherein the EO content is more than 50%, the functionality is 3, and the equivalent weight is more than 1000.

8. The self-skinning polyurethane foam rapid release composition for an automobile steering wheel according to claim 1, wherein the synthesis method of the component B modified full MDI system isocyanate prepolymer is as follows: adding MDI system isocyanate into a reactor, heating to 50 ℃, adding dehydrated polyether glycol 2, and reacting for 4 hours at 60-80 ℃ to obtain modified full MDI system isocyanate with isocyanate (NCO) content of 23-31 wt%; polyether polyol 2 is a difunctional all-propylene-oxide polyether polyol having a molecular weight of 500-10000.

9. The self-skinning polyurethane foam rapid release composition for automobile steering wheels according to claim 8, wherein the MDI system isocyanate is a mixture of carbodiimide-modified liquefied MDI and MDI-50, wherein the mass ratio of the carbodiimide-modified liquefied MDI to the MDI-50 is 50/50 to 95/5.

10. A method for preparing the self-skinning polyurethane foam rapid release composition for an automobile steering wheel according to any one of claims 1 to 9: adding the raw materials of the component A into a reactor with stirring according to a certain amount, and reacting for 1-2 hours at a constant temperature of 35 ℃ to finish the reaction to obtain a polyol component A; the prepolymer formed by pre-polymerization is the component B.

Technical Field

The invention belongs to the field of polyurethane semi-rigid foam, and particularly belongs to the field of self-skinning polyurethane foam.

Technical Field

Polyurethane semi-rigid foam (semi-rigid foam for short) is one of several large varieties of polyurethane. It is a foam with the performance between that of polyurethane soft foam and that of polyurethane hard foam, and features high compression load value and high density, and its cross-linking density is far higher than that of soft foam and second to that of hard foam. The semi-hard bubble can quickly convert kinetic energy into energy in other forms when the automobile is impacted, thereby playing a role in buffering and protecting the safety of passengers.

Polyurethane integral skin foams belong to the category of semi-rigid foams, and are the third generation products of polyurethane foam processing developed according to the rapid development of the automotive industry. The compact skin and foam core of the polyurethane self-skinning foam, also known as integral skin foam, are prepared from the same two-component material at one time. The compact surface skin can form different patterns according to different moulds, thereby being beautiful and having protection effect; the foam of the core reduces both the density and the elasticity of the article. Because of the advantages, the polyurethane self-skinning foam is widely used for manufacturing automobile steering wheels, armrests, headrests and the like. In the current self-skinning foams, as a substitute for CFC, Hydrochlorofluorocarbons (HCFC), pentanes, Hydrofluorocarbons (HFC), and water are all useful for the preparation of polyurethane self-skinning foams. HCFC-141b, the mainstream product of polyurethane blowing agents, will also be banned from use. Compared with the foaming agents, the water has the advantages of low cost, easy obtainment, no toxicity, no flammability and explosion and zero ODP value.

In addition, in order to meet the requirements of production process and production efficiency, compared with the common foam, the self-skinning foam formula needs to add more catalyst, generally 1.5-3%, so that the self-skinning product can be cured in a shorter time, the demoulding time is generally controlled to be 60-120S, and particularly, the large-scale production is controlled to be 60-90S as much as possible. However, with the development of automobile industrialization, the design of an automobile steering wheel is more and more complex, the original steering wheel is not like a circle of polyurethane foam around, a base is arranged in the middle of the existing steering wheel and is filled with the polyurethane foam, and an internal cylindrical polyurethane clamping groove is used for fixing a horn cover. The clamping grooves are generally small in opening and large in inner part, and are very easy to tear and break when being demolded early, so that the rapid demolding of steering wheel products is greatly limited.

The current common solutions are: (1) the reaction speed of the materials is accelerated, and the demolding strength is improved; (2) increasing the spraying times of the release agent; (3) and an internal release agent is added into the material to reduce the release force.

The release agent can form a layer of isolating film between the product and the mould, and can effectively prevent the formed product from being bonded with the mould, so that the product can be more easily released from the mould, and the polyurethane product with a smoother surface is obtained. If no release agent is used or the release agent is not properly selected, the product is difficult to release, the product is easy to damage, and the production efficiency is greatly reduced due to the need of repeatedly cleaning the mold. The currently used mold release agents are internal mold release agents and external mold release agents. The internal release agent is directly added into the polyurethane formulation, and because the melting point of the internal release agent is lower than the curing temperature of the polyurethane and the internal release agent is incompatible with the curing resin, the internal release agent migrates to the interface between the polyurethane and the mould to form a separation film when the polyurethane is heated, cured and molded, thereby achieving the effect of releasing the mould. However, internal mold release agents are not widely used as external mold release agents because they are usually composed of zinc stearate, amine stearate and modified polysiloxane, and their reactive groups usually affect the physical properties and reactivity of polyurethane as part of polyurethane formulation.

In the production process, in order to rapidly demould and simultaneously not tear and tear, an operator generally adopts a mode of increasing the spraying times of the demoulding agent, and the original four-mould spraying is changed into one-mould spraying, so that the using amount of the demoulding agent is increased, the cost is increased, the environment is not protected, the field smell is large, and the health is not good.

CN101602839B describes a self-skinning polyurethane-urea composition, a preparation method and application thereof, the invention adopts organic diamine as a chain extender, introduces the rapid polymerization reaction for forming polyurea, and improves the polymerization reaction speed in the polyurethane-urea forming process, thereby effectively shortening the demoulding time of water-blown self-skinning polyurethane products and achieving the purposes of energy conservation and consumption reduction. However, the organic diamine chain extender has too high reactivity, influences the fluidity of materials, and easily causes problems of dark bubbles, material shortage and the like for complex products.

CN101874051B describes a polyurethane integral foam containing cyclohexane dicarboxylic acid dialkyl ester as an internal mold release agent, and the integral foam adopts cyclohexane dicarboxylic acid dialkyl ester as the internal mold release agent, and the proposal has the defects that the internal mold release agent easily influences the skinning property of the foam, and simultaneously, the addition amount is larger, and the cost is increased. Other internal mold release agents such as polydimethylsiloxanes or fatty acid esters can interfere with foam formation. The use of these internal mold release agents can produce undesirably large cells and impair the formation of a dense skin, which is important for polyurethane integral foams.

CN1319110A discloses a compatibilization effect of an internal mold release agent, a surfactant with a special structure prepared from propylene oxide and ethylene oxide has a compatibilization effect on fatty acid ester and fatty acid amide internal mold release agents, and the internal mold release agent is kept stably dispersed in polyether polyol without phase separation; patent CN1314927A discloses an internal mold release agent for low-density reaction injection molding polyurethane foam materials, wherein a fatty acid condensation compound is used as the internal mold release agent, mineral oil is used as a mold release accelerator, the dosage of the internal mold release agent is larger and accounts for 10-30 parts of a polyol component, and the internal mold release agent and the mineral oil are added into a combined material while the internal mold release agent is added, so that the process difficulty is increased, the instability of a system is increased, and the final mechanical property of a product is easily reduced.

Therefore, there is a need for a low cost, easy to use, 60S release skin composition for complex products that improves production efficiency and yield.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a self-skinning polyurethane foam rapid demoulding composition for an automobile steering wheel.

The second object of the present invention is to provide a method for preparing the self-skinning polyurethane foam rapid release composition for an automobile steering wheel.

The first purpose of the invention is realized by the following technical scheme, and the self-skinning polyurethane foam rapid demoulding composition for the automobile steering wheel comprises A, B two components in parts by mass:

the component A comprises:

and B component:

the isocyanate prepolymer is a modified full MDI system isocyanate prepolymer with isocyanate (NCO) content of 23-31 wt%, the full MDI system isocyanate comprises a mixture of diphenylmethane diisocyanate (MDI) monomer, carbamate modified MDI, carbodiimide modified MDI and other isocyanates, and the functionality is 2.0-2.7, preferably 2.1-2.4.

The composite nano modified release agent is prepared by the following method: (1) dispersing nano calcium carbonate in toluene, adding gamma-isocyanatopropyl triethoxysilane, refluxing for 6-8h at 70-120 ℃, centrifuging, washing, and drying in vacuum to obtain modified nano calcium carbonate; (2) mixing and grinding the modified nano calcium carbonate and castor oil polyhydric alcohol according to the mass ratio of 1/1-1/2, then heating to 70-90 ℃, stirring and reacting for 1.5-3h, cooling to 15-25 ℃, and uniformly mixing with a diluent according to the mass ratio of 1/2-2/1 to obtain the nano modified release agent.

The polyether polyol 1 is high-activity polyether polyol which is initiated by glycerol, has the three-functionality degree, the molecular weight of 3000-10000 and the content of terminal primary hydroxyl groups of more than 70 percent.

The polymer polyol is high-activity polymer polyol which is grafted by styrene and acrylonitrile and has three functionality degrees and 25-45% of solid content.

The diluent is aromatic oil, naphthenic oil, paraffin oil and the like with carbon atoms more than or equal to 8.

The chain extender is selected from at least one of the following groups: ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, diethylene glycol, and the like.

There are two important types of reactions during polyurethane foam formation: gel reactions and foam reactions typically require catalysts to catalyze these two types of reactions to complete rapidly and to ensure their equilibrium. The catalyst includes organometallic catalysts and amine catalysts. Examples of common organometallic catalysts include, but are not limited to, dibutyltin dilaurate (T12), stannous octoate (T12), dibutyltin diacetate, dibutyltin bis (dodecylthio) and the like. Examples of common amine catalysts include, but are not limited to, dipropylene glycol solution (A) with a bis (dimethylaminoethyl) ether content of 70%₁) Dipropylene glycol solution (A) containing 33% of triethylenediamine₃₃) Dimethylethanolamine (DMEA), Pentamethyldiethylenetriamine (PMDETA), Tetramethylethylenediamine (TMEDA), Dimethylaminoethoxyethanol (DMAEE), and the like. The above catalysts can be used in the present invention, and the amount of the catalyst used depends on the desired reaction and curing speed, and is usually 0.2% to 4%, preferably 0.5% to 2% of the total amount of the polyether component.

The foaming agent is water.

The foam stabilizer is a commonly used foam stabilizer for semi-rigid foam and high-resilience foam, the foam stabilizer contains silicone oil with Si-C bonds, the Si-C bonds are not easy to hydrolyze, the foaming stability and the long-term storage stability of the polyether of the composition can be effectively improved, and the using amount of the foam stabilizer is 0.5-2% of the total amount of the polyether component. The variety with higher activity is preferred, and suitable foam stabilizers include, but are not limited to, B8715 and B8736 of Germany winning and creating industry group, DC2525 and DC6070 of American gas and chemical company, and L-3629 and L-3640 of American Mediterranean high-tech materials group. The foam stabilizer is used in an amount of 0.5% to 2%, preferably 0.5% to 1.5%, of the polyether component.

The cell opener of the present invention is a high Ethylene Oxide (EO) content polyether polyol, typically having an EO content greater than 50%, a functionality of 3, and an equivalent weight greater than 1000.

The synthesis method of the component B modified isocyanate prepolymer comprises the following steps:

the synthesis method of the modified full MDI system isocyanate prepolymer comprises the following steps: adding MDI system isocyanate into a reactor, heating to 50 ℃, adding dehydrated polyether glycol 2, and reacting for 4 hours at 60-80 ℃ to obtain the modified full MDI system isocyanate with the isocyanate (NCO) content of 23-31 wt%. The MDI system isocyanate is preferably a mixture of carbodiimide modified liquefied MDI and MDI-50, wherein the mass ratio of the carbodiimide modified liquefied MDI to the MDI-50 is 50/50-95/5, preferably 50/50-80/20. Wherein the carbodiimide modified MDI is preferably MM103C from BASF company or CD-C product from Cordson corporation; MDI-50 is 4, 4 '-diphenylmethane diisocyanate (4, 4' -MDI) to 2, 4 '-diphenylmethane diisocyanate (2, 4' -MDI) is 50: 50 pure MDI, such as product 0129 from Corseus corporation. Polyether polyol 2 is a difunctional all-propylene-oxide polyether polyol having a molecular weight of 500-10000.

To achieve the second object, the present invention provides a method for preparing a self-skinning polyurethane foam rapid release composition for an automobile steering wheel, comprising: putting polyether polyol 1, a chain extender, a nano modified release agent, a catalyst, a foam stabilizer, a foaming agent and a pore opening agent into a reactor with stirring, and reacting at the constant temperature of 35 ℃ for 1-2 hours to finish the reaction to obtain the polyol component A. The prepolymer formed by pre-polymerization is the component B. The component A and the component B are separately stored, and are matched for use according to the mass ratio of 100: 40-100 of the component A to the component B when in use. During production, the component A and the component B are respectively placed in A, B charging pots of a high-pressure foaming machine; keeping the temperature of the material at 30-40 ℃; the component A and the component B are injected into a steering wheel mould through a closed mould according to the mass ratio of 100: 45-65; and after 60-90 seconds, taking out the automobile steering wheel from the mold to obtain the automobile steering wheel.

Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:

the nanometer modified release agent used by the composition has the advantages of simple preparation method and low cost, can simultaneously improve the strength of a product in demoulding and reduce the demoulding force of the product, has no influence on foaming reaction, and solves the defect that a commercially available product is easy to tear and break in 60S demoulding. The composition can be used for producing steering wheels of cars and commercial vehicles, etc.

Detailed Description

The following examples are provided to better illustrate the effects of the present invention, but the present invention is not limited to the examples. The raw materials are calculated according to parts by mass except for special description.

"MDI" is an abbreviation for "diphenylmethane diisocyanate", such as 2, 4-MDI for 2, 4-diphenylmethane diisocyanate and 4, 4 '-MDI for 4, 4' -diphenylmethane diisocyanate; "NCO" is an abbreviation for "isocyanato"; the term "functionality" refers to the number of functional groups that a monomer molecule is capable of participating in a condensation polymerization reaction during polymerization. The "parts" referred to herein mean "parts by mass" unless otherwise specified; the percentage contents refer to mass percentage contents unless otherwise specified;