CN114437361A - Inorganic-organic hybrid material, preparation method thereof and application of modified polyurethane prepared from inorganic-organic hybrid material as adhesive - Google Patents

Abstract

The present application discloses an inorganic-organic hybrid material, and further discloses a preparation method of the inorganic-organic hybrid material, and uses the inorganic-organic hybrid material to modify polyurethane, first modifying phenolic by terpene The resin obtains terpene phenolic resin; then the nano-silica is modified with epoxy silane coupling agent to obtain modified nano-silica; then the terpene phenolic resin and the modified nano-silica are combined by the functional group of the silane coupling agent compounded to obtain an inorganic-organic nanocomposite material; adding oligomer polypolyol and polyisocyanate in the reaction kettle to finally obtain a modified polyurethane adhesive, the prepared adhesive has high solid content, It can be quickly cured at room temperature, has stable storage performance, and has the advantages of excellent water resistance, heat resistance and adhesive properties. It can be used in the field of high temperature and high humidity processing and production of hardwood.

Description

A kind of inorganic-organic hybrid material and preparation method, and the application of modified polyurethane prepared by utilizing the same as adhesive

technical field

The invention belongs to the field of wood adhesives, and in particular relates to an inorganic-organic hybrid material-modified polyurethane adhesive for hardwoods and a preparation method thereof. The one-component moisture-curing adhesive with stable storage performance has excellent water resistance, heat resistance and bonding properties, and can be used in the field of high temperature and high humidity processing and production of hardwood.

Background technique

One-component moisture-curing polyurethane adhesive is a kind of adhesive containing strong polarity and high chemical activity urethane structure (—NHCOO—), which can be cured at room temperature, high bonding strength and flexible film. , impact resistance, wear resistance and good low temperature resistance, etc., the use in the wood processing industry, especially in the hardwood furniture industry has increased rapidly. In the production process of modern furniture, the wood needs to be baked at high temperature, and the moisture content of the wood should not exceed 12% to prevent the furniture from cracking due to changes in temperature and humidity during use. The adhesive strength, water resistance, heat resistance and other properties put forward higher requirements. However, polar groups such as urethane, allophanate, ether group, and ester group on the polyurethane molecular chain are prone to softening and decomposition at high temperatures, resulting in a sharp decline in mechanical properties, resulting in ordinary polyurethane polymers only For long-term use below 80 °C, the short-term use temperature cannot exceed 120 °C; at the same time, the presence of ester groups also affects the water resistance of the adhesive layer. Therefore, how to improve the heat resistance, water resistance and bonding strength of polyurethane adhesives to meet the requirements of modern wood furniture production is an urgent problem to be solved at present.

The application number is 201810679952.9 The Chinese invention patent application discloses a preparation method of a heat-resistant polyurethane composite material. On the one hand, by increasing the benzene ring content and polar group content in the hard segment, the rigidity and hydrogen of the hard segment are increased. On the other hand, fillers and additives such as styrene, lutein, silica, nano-silica, and kaolin are added to improve the heat resistance of polyurethane materials. However, the reaction rate of this technology is slow, because the steric hindrance effect of the benzene ring leads to incomplete end capping. At the same time, due to the addition of a large amount of inorganic fillers, although the heat resistance of the composite material can be improved to a certain extent, it also affects the compatibility with organic high Compatibility and storage stability of molecular polyurethanes.

The Chinese invention patent application with the application number of 201811439191.6 discloses a phenolic resin modified polyurethane/polyurea coating and a preparation method thereof. The phenolic resin is introduced into the molecular chain of the polyurethane/polyurea, and the phenolic resin contains more benzene ring rigid groups , the rigid segment of the molecular chain increases, and the hardness and tensile strength of the coating also increase, but the improvement of the heat resistance of polyurethane/polyurea in this technology is mainly determined by the addition of halogenated polyether polyols, and phenolic Resin has no direct connection.

The application number is 201711091118.X Chinese invention patent application discloses a room temperature rapid moisture curing wood adhesive and its preparation method and application. The adhesive is composed of a main agent and a curing agent. After the main agent and curing agent The selection and preparation of the raw material components of the agent and its preparation, separate storage and treatment, and preparation before use, although the bonding performance is better when used for wood bonding, and the volatile components are less, but this method also has some shortcomings: two-component moisture curing Adhesives need to be prepared as needed. The operation is not easy and it is easy to cause waste of residual glue. The moisture curing time (25°C) exceeds 12 hours, and the storage time (25°C) is only about 150 days.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an inorganic-organic hybrid material modified hardwood adhesive and a preparation method thereof. The prepared inorganic-organic hybrid material modified hardwood polyurethane adhesive is A one-component moisture-curing adhesive with high solid content, fast curing at room temperature and stable storage performance. It has excellent water resistance, heat resistance and bonding properties. It can be used in high temperature and high humidity processing and production of hardwood. .

According to one aspect of the present application, an inorganic-organic hybrid material is provided.

An inorganic-organic hybrid material, the chemical formula of the inorganic-organic hybrid material is:

In a second aspect of the present application, a method for preparing the above-mentioned inorganic-organic hybrid material is provided.

The preparation method of the above-mentioned inorganic-organic hybrid material, the preparation steps are as follows:

(1) obtain modified nano-silica, modified phenolic resin;

(2) in the reaction vessel, the modified nano-silicon dioxide, toluene and benzyltriethylammonium chloride obtained in step (1) are mixed to obtain reaction solution I;

(3) mixing modified phenolic resin and toluene solution to obtain reaction solution II;

(4) Mix the reaction solution I obtained in step (2) with the reaction solution II obtained in step (4), and react to obtain the inorganic-organic hybrid material.

Optionally, the modified nano-silica is silica modified by a silane coupling agent;

Specifically, the method for synthesizing modified nano-silica is as follows: mixing, heating and reacting nano-silica, epoxy silane coupling agent and toluene to obtain the modified nano-silica.

Preferably, the silane coupling agent is selected from 3-(2,3 glycidoxy)propyltrimethoxysilane, 3-(2,3 glycidoxy)propyltriethoxysilane, 2- At least one of (3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

Optionally, the modified phenolic resin is a terpene-modified phenolic resin;

Specifically, the method for synthesizing the modified phenolic resin is as follows: adding phenol into a reactor, raising the temperature, adding dropwise an aqueous formaldehyde solution containing concentrated sulfuric acid, then adding dropwise terpenes, and reacting to obtain the modified phenolic resin.

Preferably, the terpene is selected from at least one of α-pinene, β-pinene, limonene, and camphene.

Optionally, in the reaction solution 1, the proportioning of modified nano-silica, toluene, benzyl tris and ammonium chloride, in parts by weight, is: (2-5): (50-100): (0.006-0.025);

In the reaction solution II, the proportion of the modified phenolic resin and the toluene solution, in parts by weight, is: (20-30):(50-100).

Optionally, in the reaction in the step (4), the reaction temperature is 100-110° C., and the reaction time is 2-3 h.

A third aspect of the present application provides an inorganic-organic hybrid material-modified polyurethane.

A polyurethane modified by an inorganic-organic hybrid material, the inorganic-organic hybrid material is the inorganic-organic hybrid material obtained by the above-mentioned inorganic-organic hybrid material and/or the above-mentioned preparation method of the inorganic-organic hybrid material. chemical material.

The inventors of the present application have found that when the inorganic/organic hybrid material is introduced into the polyurethane molecular chain, on the one hand, the phenolic hydroxyl group on the terpene phenolic resin (functionality>2) reacts with the isocyanate group on the polyurethane chain to increase the cross-linking effect. The content of rigid benzene ring segments in the network sites and molecular hard segments enhances the cohesive strength and intermolecular force of the polymer; on the other hand, nano-silica is introduced into the polyurethane chain through bonding, making the nanoparticles unique The heat resistance and mechanical properties are introduced into the polymer, which improves the bonding strength and heat resistance of the composite adhesive; thirdly, the phenolic hydroxyl group on the phenolic resin, the epoxy group on the nano-silica and the isocyanate on the polyurethane chain Through the bonding of chemical bonds, the base effectively solves the compatibility problem between inorganic nano-silica, organic terpene phenolic resin and polyurethane resin, and improves the storage stability of the composite adhesive.

The fourth aspect of the present application provides a method for preparing the above-mentioned inorganic-organic hybrid material-modified polyurethane.

The inventors of the present application found that the terpene-modified phenolic resin effectively solved the problem of poor solubility of the phenolic resin in organic solvents, increased the content of rigid benzene ring structures in the phenolic resin, and enhanced the thermal stability of the resin . Through the hydrolysis condensation of alkoxy groups on the coupling agent and the hydroxyl groups on the surface of silica, the surface of nanoparticles is organically modified and modified, which can effectively reduce the content of hydroxyl groups on the surface of the particles, improve the degree of organicization, and enhance the compatibility with organic polymers. Take advantage of the mechanical properties and heat resistance of nanomaterials.

A method for preparing the above-mentioned inorganic-organic hybrid material modified polyurethane, the steps are as follows:

In the reaction vessel, the polyisocyanate is mixed with the oligomer polypolyol, the first catalyst is added, and the reaction I is used to measure the NCO content of the reactant. When the NCO content of the reactant reaches the theoretical design value, a binary chain extender is added to react. II, measure the NCO content of the reactant, when the NCO content of the reactant reaches the theoretical design value, add the inorganic-organic hybrid material, react III, measure the NCO content of the reactant, when the NCO content of the reactant reaches the theoretical design value, cool down, add The diluent is added, and the second catalyst is added to obtain the inorganic-organic hybrid material modified polyurethane.

The inventors of the present application found that the terpene phenolic resin and the inorganic nano-silica are compounded through the reaction between the epoxy group of the silane coupling agent and the phenolic hydroxyl group on the terpene phenolic resin to generate chemical bonding, effectively combining the organic The respective advantages of the component and the inorganic component enable the preparation of a highly heat-resistant inorganic/organic hybrid material and improve the compatibility of the inorganic/organic hybrid material with polymers.

Optionally, the polyisocyanate is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane-4,4'-diisocyanate;

Preferably, the oligomeric polyol is selected from polypropylene oxide diol, polytetrahydrofuran ether diol, polyethylene adipate diol, poly-1,4-butanediol adipate diol at least one of alcohols;

Preferably, the average molecular weight of the oligomer polyol is 2000-5000;

Preferably, the first catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate, and stannous octoate;

Preferably, the diluent is selected from at least one of acetone, butanone, ethyl acetate and butyl acetate;

Preferably, the second catalyst is selected from bis(2,6-dimethylmorpholinoethyl)ether, 1,2,4-trimethylpiperazine, 1,3-dimethyl-2-imidazole at least one of the citronones;

Preferably, the binary chain extender is selected from at least one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and diethylene glycol.

Optionally, the material ratio, in terms of mass points, is:

Optionally, in the reaction I, the temperature of the reaction is 80-90 ° C, and the time of the reaction is 2-6h;

Preferably, in the reaction II, the reaction temperature is 75-80° C., and the reaction time is 2-3 h;

Preferably, in the reaction III, the reaction temperature is 75-80° C., and the reaction time is 2-4 h.

Optionally, before adding the first catalyst and the binary chain extender, the temperature needs to be lowered to 60-65°C;

Preferably, the binary chain extender needs to be added slowly, and the temperature in the reaction vessel is controlled during the addition, so that the temperature in the reaction vessel is between 65-75°C;

Preferably, the temperature in the reaction vessel needs to be lowered to between 35-45°C before adding the diluent.

A fifth aspect of the present application provides a special adhesive for wood, which is the above-mentioned inorganic-organic hybrid material-modified polyurethane and/or the inorganic-organic hybrid material-modified polyurethane obtained by the above method. .

The inventors of the present application have found that the inorganic/organic hybrid material-modified hardwood adhesive prepared by the above preparation method is a one-component moisture-curing adhesive with high solid content, which can pass through the air at room temperature. The moisture quickly cures without glue, which improves the production efficiency of the downstream industry.

The beneficial effects that this application can produce include:

1) The terpene-modified phenolic resin provided by the application effectively solves the problem of poor solubility of the phenolic resin in organic solvents, increases the content of the rigid benzene ring structure in the phenolic resin, and enhances the thermal stability of the resin. .

2) The silane coupling agent modified nano-silica provided in this application can effectively reduce the hydroxyl content on the particle surface, improve the degree of organicization, enhance the compatibility with organic polymers, and give full play to the mechanical properties and heat resistance of nanomaterials. sex.

3) The inorganic-organic hybrid material provided in the present application realizes the preparation of a highly heat-resistant inorganic-organic hybrid material, and improves the compatibility of the inorganic-organic hybrid material with the polymer.

4) The inorganic-organic hybrid material-modified hardwood adhesive provided in this application improves the storage stability of the composite adhesive, and can be rapidly cured by moisture in the air at room temperature, without the need for compounding. , improve the production efficiency of downstream industries.

5) The modified polyurethane adhesive provided by this application is a one-component moisture-curing adhesive with high solid content, which can be rapidly cured at room temperature, has stable storage performance, and has excellent water resistance, heat resistance and bonding performance. Room temperature humidity curing time (25℃) is ≤4 hours, storage time (25℃) ≥240 days, tensile strength ≥20.5MPa, normal compressive shear strength ≥19.7MPa, wet compressive shear strength ≥11.3Mpa, 50 % Thermogravimetric temperature ≥425℃, it can be used in the field of high temperature and high humidity processing and production of hardwood.

Description of drawings

FIG. 1 is a chemical structure diagram of the silane coupling agent-modified nano-silica obtained in Example 1 of the application.

Fig. 2 is the infrared spectrogram of the modified polyurethane adhesive obtained in Example 1 of the application.

Detailed ways

The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and catalysts in the examples of this application are purchased through commercial channels, wherein the silane coupling agent is purchased from Aladdin reagent; nano-SiO ₂ is purchased from Zhejiang Zhoushan Mingri Nano Materials Co., Ltd.; polyisocyanate is purchased from Wan Hua Chemical Group Co., Ltd.; oligomer polyols were purchased from Asahikawa Chemical (Suzhou) Co., Ltd.; catalysts were purchased from Guangzhou Chemical Reagent Factory; binary chain extenders were purchased from Tianjin Yongda Chemical Reagent Co., Ltd.

The thermal stability was measured on a German NETZSCH STGA 449C comprehensive thermal analyzer;

The tensile properties of the film were measured by an Instron 3367 testing machine from Instron, UK;

The compressive shear strength of wood was tested with a compressive shear strength tester from Tonichi Instruments.

The analytical method in the embodiment of the application is as follows:

Moisture curing time:

Place the sample in an environment of 25±2°C and relative humidity of 50±10% for moisture curing, test the normal compressive shear strength of the sample at regular intervals, and record the time required for the sample adhesive strength to reach the maximum.

Storage time:

The storage time of the samples was evaluated according to GB/T14074.9-1993 wood adhesive and its resin test method.

Normal and wet compressive shear strength:

The normal and wet compressive shear strengths of the samples were evaluated according to the method of LY/T 1601-2011 water-based polymer-isocyanate wood adhesive.

Tensile Strength:

The tensile strength of the samples was evaluated according to GB/T 528-2009 Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber.

Thermal stability:

Using a thermogravimetric analyzer, nitrogen protection, the measurement temperature range is 30-600 °C, the heating rate is 10 °C/min, and the sample mass is 10 mg.

NCO (solid content) determination:

The percentage of NCO in the reaction system was determined by titration every 30 minutes.

In addition, in the embodiments described in this application, the raw materials are all taken as the unit of weight (g).

Example 1

1) Preparation of terpene-modified phenolic resin

90g of phenol was added to a four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser tube and a constant pressure dropping funnel, heated and melted, and 55g of aqueous formaldehyde solution containing 0.36g of concentrated sulfuric acid was added dropwise within 1.5h when the temperature was raised to 100°C. Reflux for 1 hour, then install a water separator between the flask and the condenser, and add 156 g of α-pinene dropwise within 1 hour until the temperature rises to 150 °C and then keep the temperature for 4 hours. The reaction components and the distillation residue are the product terpene-modified phenolic resin after vacuum drying;

2) Preparation of Silane Coupling Agent Modified Nano-Silica

After ultrasonically dispersing 7g of completely vacuum-dried and dehydrated nano-silica, 25g of 3-(2,3 glycidoxy)propyltrimethoxysilane and 100g of toluene for 0.5h, they were added to a chamber equipped with a mechanical stirrer, a thermometer and a condenser. Start stirring and heating in the four-necked flask, condense and reflux for 4 hours at 75°C, then cool and centrifuge to obtain precipitation, repeatedly wash with absolute ethanol to remove unreacted silane coupling agent, vacuum dry and grind to obtain Silane coupling agent modified nano silica;

3) Preparation of inorganic-organic hybrid materials

Take 5g of modified nano-silicon dioxide, 70g of toluene, and 0.02g of benzyltriethylammonium chloride in a flask, disperse by ultrasonic for 30min for later use, and add 25g of terpene phenolic resin and 70g of toluene into a four-necked flask. Heating and stirring at 60 °C to dissolve, then adding the ultrasonically dispersed modified nano-silica toluene solution, mixing and stirring, heating to 100 °C for 2 hours, and drying in a vacuum drying oven at 90 °C for 2 hours to obtain modified nano-silica and terpenes. Inorganic-organic hybrid material composited with alkene phenolic resin;

4) Synthesis of Polyurethane Adhesive for Hardwood Modified by Inorganic-Organic Hybrid Materials

85g of poly-1,4-butanediol adipate diol 3000 was added to a four-necked flask with a mechanical stirrer and a thermometer, heated to 120°C, vacuum dehydrated for 2 hours until no bubbles were generated in the flask, and then filled with nitrogen The temperature was lowered to 60°C, 80g of toluene diisocyanate and 0.03g of the first catalyst dibutyltin dilaurate were added to the flask in turn, the temperature was raised to 80°C and the reaction was carried out for 4h, until the NCO content of the polyurethane prepolymer reached the theoretical design value, then the temperature was lowered to 65 ℃, slowly add 5 g of ethylene glycol, and control the temperature of the system not to exceed 75 ℃, after the dropwise addition, the temperature is raised to 78 ℃ for 2 hours, and when the NCO content of the prepolymer reaches the theoretical design value, 15 g of inorganic-organic hybrid material is added and Continue the reaction for 3h until the NCO content of the polymer reaches a stable value, then cool down to 35°C, add 60g of diluent ethyl acetate and 1g of the second catalyst 1,2,4-trimethylpiperazine, and seal it to obtain a solid. Polyurethane adhesive for hardwood modified with 90% inorganic-organic hybrid material.

Fig. 1 is the infrared spectrum of the polyurethane adhesive for hardwood modified by inorganic-organic hybrid material in Example 1, it can be seen that Si-O-Si appears at 1108cm ^-1 , 812cm ^-1 and 469cm ^-1 The characteristic absorption peak of epoxy group disappears at 917cm ^-1 , and the stretching vibration absorption peak of benzene ring skeleton appears at 1601cm ^-1 and 1506cm ^-1 , indicating that the silane coupling agent has successfully combined nano-silica and The terpene phenolic resin is compounded; and the characteristic absorption peaks of stretching vibration of -NH and C=O appear at 3365cm ^-1 and 1730cm ^-1 respectively, and the bending vibration peak of -NH- at 1557cm ^-1 and 1262cm ^-1 And 1170cm ^-1 is the stretching vibration peak of -COO ^- , indicating the formation of the urethane structure in the reaction; from the results in Figure 1, it can be seen that a kind of inorganic-organic hybrid material modified polyurethane adhesive for hardwood successful synthesis.

Example 2

1) Preparation of terpene-modified phenolic resin

80g of phenol was added to a four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser tube and a constant pressure dropping funnel, heated and melted. When the temperature was raised to 100°C, 70g of aqueous formaldehyde solution containing 0.4g of concentrated sulfuric acid was added dropwise within 2h, and the mixture was kept mixed. The liquid was boiled and refluxed for 1.5h, then a water separator was installed between the flask and the condenser, and 145g of β-pinene was added dropwise within 1h until the temperature rose to 150°C and then kept for 2h. After the reaction was completed, the temperature was raised to above 250°C and reduced pressure The unreacted components are removed by distillation, and the distillation residue is the product terpene-modified phenolic resin after vacuum drying;

2) Preparation of Silane Coupling Agent Modified Nano-Silica

After ultrasonically dispersing 5g of completely vacuum-dried and dehydrated nano-silicon dioxide, 20g of 3-(2,3 glycidoxy)propyltriethoxysilane and 125g of toluene for 1 hour, they were added to a chamber equipped with a mechanical stirrer, a thermometer and a condenser. Start stirring and heating in the four-necked flask, condense and reflux at 70°C for 3 hours, then cool and centrifuge to obtain a precipitate, repeatedly wash with absolute ethanol to remove unreacted silane coupling agent, vacuum dry and grind to obtain silane coupling agent Joint agent modified nano-silica;

3) Preparation of inorganic-organic hybrid materials

Take 3g of modified nano-silicon dioxide, 80g of toluene, and 0.01g of benzyltriethylammonium chloride in a flask, disperse it ultrasonically for 30min for later use, and add 20g of terpene phenolic resin and 80g of toluene into a four-necked flask. Heating and stirring at 60 °C to dissolve, then adding ultrasonically dispersed modified nano-silica toluene solution, mixing and stirring, heating to 110 °C for 3 hours, and then drying in a vacuum drying oven at 90 °C for 3 hours to obtain modified nano-silica and terpenes. Inorganic-organic hybrid material composited with alkene phenolic resin;

4) Synthesis of Polyurethane Adhesive for Hardwood Modified by Inorganic-Organic Hybrid Materials

Add 60g of polytetrahydrofuran ether diol 2000 to a four-necked flask with a mechanical stirrer and a thermometer. After heating to 120 °C, vacuum dehydration for 2 hours until no bubbles are generated in the flask, then fill with nitrogen to cool down to 65 °C, and add to the flask in turn. 70g of hexamethylene diisocyanate and 0.02g of the first catalyst dibutyltin diacetate were heated to 85°C and reacted for 3h until the NCO content of the polyurethane prepolymer reached the theoretical design value, then the temperature was lowered to 60°C, and 4g of 1,3- Propylene glycol, and control the temperature of the system not to exceed 75 °C, after the dropwise addition, the temperature was raised to 78 °C and kept for 3 hours. When the NCO content of the prepolymer reached the theoretical design value, 30 g of inorganic-organic hybrid material was added to react for 2 hours until the NCO of the polymer was reached. When the content reaches a stable value, the temperature is lowered to 35°C, 41g of diluent butanone and 2g of the second catalyst 1,3-dimethyl-2-imidazolidinone are added, and sealed and stored to obtain an inorganic-organic solid content of 80%. Hybrid material-modified polyurethane adhesive for hardwoods.

Example 3

1) Preparation of terpene-modified phenolic resin

According to the above ratio, 100g of phenol was added to the four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser tube and a constant pressure dropping funnel, and heated and melted. Keep the mixture boiled and refluxed for 1h, then install a water separator between the flask and the condenser, add 170g of limonene dropwise within 1h, until the temperature rises to 150°C and then keep the temperature for 2h. After the reaction is completed, the temperature is raised to 250°C. The unreacted components are removed by vacuum distillation above ℃, and the distillation residue is the product terpene-modified phenolic resin after vacuum drying;

2) Preparation of Silane Coupling Agent Modified Nano-Silica

After 10g of completely vacuum-dried and dehydrated nano-silica, 30g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 150g of toluene were ultrasonically dispersed for 0.5h, they were added to a device equipped with a mechanical stirrer, a thermometer and a condenser. Start stirring and heating in the four-necked flask, and condensing and refluxing for 5 hours at 75 °C, then cooling and centrifuging to obtain a precipitate, repeatedly washing with absolute ethanol to remove the unreacted silane coupling agent, vacuum drying and grinding to obtain silane Coupling agent modified nano silica;

3) Preparation of inorganic-organic hybrid materials

Take 2g of modified nano-silica, 50g of toluene, and 0.01g of benzyltriethylammonium chloride in a flask, disperse by ultrasonic for 30min for later use, add 30g of terpene phenolic resin and 50g of toluene into a four-necked flask, and put it in a four-necked flask. Heating and stirring at 60 °C to dissolve, then adding the ultrasonically dispersed modified nano-silica toluene solution, mixing and stirring, heating to 105 °C, reacting for 2 hours, and drying in a vacuum drying oven at 90 °C for 3 hours to obtain modified nano-silica and terpenes. Inorganic-organic hybrid material composited with alkene phenolic resin;

4) Synthesis of Polyurethane Adhesive for Hardwood Modified by Inorganic-Organic Hybrid Materials

100g of polyethylene adipate diol 5000 was added to a four-necked flask with a mechanical stirrer and a thermometer, heated to 120°C, vacuum dehydrated for 2 hours until no bubbles were generated in the flask, and then filled with nitrogen and cooled to 60°C, Add 60g isophorone diisocyanate and 0.05g first catalyst stannous octoate to the flask in turn, heat up to 90 °C for reaction for 2 h, until the NCO content of the polyurethane prepolymer reaches the theoretical design value, cool down to 60 °C, slowly add 6g 1,4-butanediol, and control the temperature of the system not to exceed 75°C. After the dropwise addition, the temperature was raised to 80°C for 2 hours. When the NCO content of the prepolymer reached the theoretical design value, 35g of inorganic-organic hybrid materials were added to react for 4 hours. , until the NCO content of the polymer reaches a stable value, cool down to 35 ° C, add 35 g of diluent butyl acetate and 1.8 g of the second catalyst bis(2,6-dimethylmorpholinoethyl) ether, and seal it, that is, A polyurethane adhesive for hardwood modified by inorganic-organic hybrid material with a solid content of 85% was obtained.

Example 4

1) Preparation of terpene-modified phenolic resin

According to the above proportioning, 90g of phenol was added to the four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser tube and a constant pressure dropping funnel and heated and melted. The formaldehyde solution was refluxed for 1h, then a water separator was installed between the flask and the condenser, and 160g of camphene was added dropwise within 1h, until the temperature rose to 150°C, and the temperature was kept constant for 3h. After the reaction was completed, the temperature was raised to above 250°C and reduced The unreacted components are removed by pressure distillation, and the distillation residue is the product terpene-modified phenolic resin after vacuum drying;

2) Preparation of Silane Coupling Agent Modified Nano-Silica

After ultrasonically dispersing 8g of completely vacuum-dried and dehydrated nano-silicon dioxide, 25g of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 125g of toluene for 1 hour, they were added to a device equipped with a mechanical stirrer, a thermometer and a condenser. Start stirring and heating in a four-necked flask, react at 75 °C for 6 hours, then cool and centrifuge to obtain a precipitate, repeatedly wash with absolute ethanol to remove unreacted silane coupling agent, vacuum dry and grind to obtain silane coupling agent-modified nano-silica;

3) Preparation of inorganic-organic hybrid materials

Take 4g of modified nano-silicon dioxide, 90g of toluene, and 0.02g of benzyltriethylammonium chloride in a flask, disperse by ultrasonic for 30min for later use, take 25g of terpene phenolic resin, and 90g of toluene into a four-necked flask. Heating and stirring at 60 °C to dissolve, then adding ultrasonically dispersed modified nano-silica toluene solution, mixing and stirring, heating to 110 °C for 2 hours, and drying in a vacuum drying oven at 90 °C for 2 hours to obtain modified nano-silica and terpenes. Inorganic-organic hybrid material composited with alkene phenolic resin;

4) Synthesis of Polyurethane Adhesive for Hardwood Modified by Inorganic-Organic Hybrid Materials

90g of polyoxypropylene glycol 4000 was added to a four-necked flask with a mechanical stirrer and a thermometer, heated to 120°C, dehydrated under vacuum for 2 hours until no bubbles were generated in the flask, then filled with nitrogen and cooled to 60°C, and added to the flask in turn. 80g of diphenylmethane-4,4'-diisocyanate and 0.04g of dibutyltin maleate as the first catalyst were heated to 80°C and reacted for 6h until the NCO content of the polyurethane prepolymer reached the theoretical design value, then the temperature was lowered to 65°C , slowly add 3g of 1,6-hexanediol, and control the temperature of the system not to exceed 75 °C. After the dropwise addition, the temperature is raised to 78 °C for 3 h. When the NCO content of the prepolymer reaches the theoretical design value, add 20 g of inorganic-organic hybrid The material continued to react for 4 hours until the NCO content of the polymer reached a stable value, then cooled to 35°C, added 48g of diluent ethyl acetate and 1.5g of the second catalyst 1,3-dimethyl-2-imidazolidinone, and sealed it for storage , that is, a polyurethane adhesive for hardwood modified by an inorganic-organic hybrid material with a solid content of 80% is obtained.

Comparative Example 1

Synthesis of Polyurethane Adhesive

80g of polyoxypropylene glycol 2000 was added to a four-necked flask with a mechanical stirrer and a thermometer, heated to 120°C, dehydrated in a vacuum for 2 hours until no bubbles were formed in the flask, then filled with nitrogen and cooled to 60°C, and added to the flask in turn. 80g of diphenylmethane-4,4'-diisocyanate and 0.04g of the first catalyst dibutyltin dilaurate were heated to 85°C and reacted for 6h until the NCO content of the polyurethane prepolymer reached the theoretical design value, then the temperature was lowered to 65°C , slowly add 6g of 1,6-hexanediol, and control the temperature of the system not to exceed 75 °C, after the dropwise addition, the temperature is raised to 78 °C for 3 hours, when the NCO content of the prepolymer reaches the theoretical design value, cool down to 35 °C, add 18g The diluent ethyl acetate and 1.8 g of the second catalyst 1,3-dimethyl-2-imidazolidinone are sealed and stored to obtain a polyurethane adhesive for hardwood modified by an inorganic-organic hybrid material with a solid content of 90%. agent.

Comparative Example 2

According to the method described in Application No. 201711091118.X, a room temperature rapid moisture curing wood adhesive was prepared.

Comparative Example 3

A phenolic resin modified polyurethane/polyurea coating was prepared according to the method described in Application No. 201811439191.6.

According to the aforementioned test method, the samples of Examples 1-4 and Comparative Examples 1-3 were subjected to performance analysis, and the results obtained are shown in Table 1.

Table 1

The invention mainly solves the technical problems of long moisture curing time, short storage time, low bonding strength and poor water resistance and heat resistance stability of the existing single-component moisture curing polyurethane adhesive. As can be seen from Table 1, the polyurethane adhesives for hardwood modified by inorganic-organic hybrid materials prepared according to Examples 1 to 4 of the present invention have improved comprehensive performance compared with the prior art. Compared with the prior art, according to Examples 1 to 4, the present invention firstly prepares terpene-modified phenolic resin, then prepares silane coupling agent-modified nano-silica, and then uses silane coupling agent to combine terpene-modified phenolic resin with phenolic resin. The modified nano-silica is compounded to obtain an inorganic-organic hybrid material, which is finally used for the modification of polyurethane to obtain a polyurethane adhesive for hardwood modified by the inorganic-organic hybrid material. The one-component moisture-curing polyurethane adhesive of the present invention has shorter moisture-curing time and better storage stability. At the same time, it can also be seen from Table 1 that due to the introduction of inorganic-organic hybrid materials, the present invention Compared with Comparative Examples 2 and 3 prepared by the prior art, the adhesives prepared in Examples 1 to 4 have higher tensile strength, adhesive strength and better water and thermal stability.

Compared with the prior art, the present invention uses terpene-modified phenolic resin, which effectively solves the problem of poor solubility of phenolic resin in organic solvents, increases the content of rigid benzene ring structures in the phenolic resin, and enhances the resin's properties. Mechanical properties and thermal stability; use silane coupling agent to organically modify the surface of nano-silica particles, and combine terpene phenolic resin and nano-silica particles through coupling agent to improve the adhesion with polymers. compatibility, and give full play to the mechanical properties and thermal stability advantages of nanomaterials. At the same time, the multifunctional group on the nanocomposite reacts with the isocyanate group to increase the crosslinking network site, improve the crosslinking density of the adhesive, and form a more complex three-dimensional crosslinking network structure, thereby improving the tensile strength of the adhesive. , Adhesion strength, water, thermal stability.

The above are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Without departing from the scope of the technical solution of the present application, any changes or modifications made by using the technical content disclosed above are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims (10)

1. An inorganic-organic hybrid material, wherein the structural formula of the inorganic-organic hybrid material is as follows:

wherein n is in the range of 5-20.

2. A method for preparing the hybrid inorganic-organic material according to claim 1, comprising the following steps:

(1) obtaining modified nano silicon dioxide and modified phenolic resin;

(2) mixing the modified nano-silica obtained in the step (1), toluene and benzyltriethylammonium chloride in a reaction vessel to obtain a reaction solution I;

(3) mixing the modified phenolic resin and a toluene solution to obtain a reaction solution II;

(4) and (3) mixing the reaction liquid I obtained in the step (2) with the reaction liquid II obtained in the step (4) for reaction to obtain the inorganic-organic hybrid material.

3. The method for preparing an inorganic-organic hybrid material according to claim 2, wherein the modified nano silica is silica modified with a silane coupling agent;

preferably, the silane coupling agent is selected from at least one of 3- (2, 3-glycidoxy) propyltrimethoxysilane, 3- (2, 3-glycidoxy) propyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane and 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane;

preferably, the modified phenolic resin is terpene-modified phenolic resin;

preferably, the terpene is selected from at least one of alpha-pinene, beta-pinene, limonene and camphene;

preferably, in the reaction solution I, the ratio of the modified nano-silica, the toluene, the benzyl tris and the ammonium chloride is, in parts by weight: (2-5): (50-100): 0.006-0.025);

in the reaction liquid II, the proportion of the modified phenolic resin to the toluene solution is as follows by weight: (20-30): 50-100);

preferably, the reaction in the step (4) is carried out at the temperature of 100 ℃ and 110 ℃ for 2-3 h.

4. An inorganic-organic hybrid material-modified polyurethane, wherein the inorganic-organic hybrid material is the inorganic-organic hybrid material according to claim 1 and/or the inorganic-organic hybrid material obtained by the method for producing an inorganic-organic hybrid material according to any one of claims 2 to 3.

5. A method for preparing the inorganic-organic hybrid material modified polyurethane of claim 4, which comprises the following steps:

in a reaction vessel, mixing polyisocyanate and oligomer polyalcohol, adding a first catalyst, reacting I, measuring the NCO content of a reactant, adding a binary chain extender when the NCO content of the reactant reaches a theoretical design value, reacting II, measuring the NCO content of the reactant, adding an inorganic-organic hybrid material when the NCO content of the reactant reaches the theoretical design value, reacting III, measuring the NCO content of the reactant, cooling when the NCO content of the reactant reaches the theoretical design value, adding a diluent, and adding a second catalyst to obtain the inorganic-organic hybrid material modified polyurethane.

6. The method for preparing inorganic-organic hybrid material-modified polyurethane according to claim 5, wherein:

the polyisocyanate is at least one selected from toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and diphenylmethane-4, 4' -diisocyanate;

preferably, the oligomeric polyol is selected from at least one of polyoxypropylene glycol, polytetrahydrofuran ether glycol, polyethylene adipate glycol, and 1, 4-butanediol adipate glycol;

preferably, the oligomeric polymeric polyol has an average molecular weight of 2000-;

preferably, the first catalyst is at least one selected from dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate and stannous octoate;

preferably, the diluent is selected from at least one of acetone, butanone, ethyl acetate and butyl acetate;

preferably, the second catalyst is selected from at least one of bis (2, 6-dimethylmorpholineethyl) ether, 1,2, 4-trimethylpiperazine, 1, 3-dimethyl-2-imidazolidinone;

preferably, the binary chain extender is at least one selected from the group consisting of ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, and diethylene glycol.

7. The method for preparing inorganic-organic hybrid material modified polyurethane as claimed in claim 6, wherein the material ratio is, by mass:

8. the method for preparing inorganic-organic hybrid material modified polyurethane according to claim 5, wherein the reaction I is carried out at 80-90 ℃ for 2-6 h;

preferably, the reaction temperature of the reaction II is 75-80 ℃, and the reaction time is 2-3 h;

preferably, the reaction temperature of the reaction III is 75-80 ℃, and the reaction time is 2-4 h.

9. The method for preparing inorganic-organic hybrid material-modified polyurethane according to claim 5, wherein: the temperature is reduced to 60-65 ℃ between the addition of the first catalyst and the binary chain extender;

preferably, the binary chain extender is added slowly, and the temperature in the reaction vessel is controlled during the addition so that the temperature in the reaction vessel is between 65 and 75 ℃;

preferably, the temperature in the reaction vessel is also reduced to between 35-45 ℃ prior to addition of the diluent.

10. An adhesive specially used for wood, characterized in that the adhesive specially used for wood comprises polyurethane modified by inorganic-organic hybrid material according to claim 4 and/or polyurethane modified by inorganic-organic hybrid material obtained by the method according to claims 5-9.

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