CN110156952A - A dual-curable polyurethane toughening resin and its preparation method and application - Google Patents

Abstract

It is a kind of can the polyurethane toughened resin of dual cure preparation method, include the following steps: S1, take the oxetanes containing hydroxyl, crylic acid hydroxy ester, diisocyanate, polymerization inhibitor, catalyst hybrid reaction, it is spare to obtain the semiclosed composition C of isocyanates；S2, addition macromolecular polyol keep 60-90 DEG C of reaction 2-8h into composition C, and i.e. acquisition can the polyurethane toughened resin of dual cure.Advantage is: polyurethane toughened resin of the invention can carry out the dual photocuring of free radical-cation or radical UV curing-cation heat cure dual cure；Curing rate can be promoted, volume contraction is small when solidification, promotes system to the adhesive force of substrate；The polyurethane toughened resin of the present invention is added to cycloaliphatic epoxy resin system by a certain percentage can effectively promote the elasticity, extensibility, toughness of system, and oxa- Ding Huanwei four-membered ring, and volume contraction is small when solidification, can promote system to the adhesive force of substrate.

Description

A dual-curable polyurethane toughening resin and its preparation method and application

technical field

The invention relates to the fields of ultraviolet light curing and cationic curing, in particular to a dual-curable polyurethane toughening resin and its preparation method and application.

Background technique

Cycloaliphatic epoxy resin is a kind of epoxy resin that is widely used. It has the advantages of light color, low viscosity, small shrinkage of curing volume, good adhesion and high temperature resistance. However, there are also problems such as low elongation, high stress, and easy sagging, which limit its use in environments with large changes in high and low temperatures.

Therefore, how to toughen cycloaliphatic epoxy resins has always been a research hotspot. Traditional toughening methods include adding nanoparticles, core-shell rubber, introducing non-curable resin components, and modifying epoxy resin itself. However, these The methods have certain limitations. For example, the introduction of nanoparticles and core-shell rubber will affect the transparency and prone to problems of poor dispersion and poor storage stability; the introduction of non-curable resin components will reduce the curing speed, affect the product's tolerance to solvents, and easily occur Migration; the process of modifying the epoxy resin itself is cumbersome and the cost is high, and some good properties of the modified epoxy resin itself may change, such as Tg reduction, adhesion decline, etc.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned technical defects, and provide a dual-curable polyurethane toughening resin and its preparation method and application. Radical photocuring, therefore, the resin of the present invention can be free radical-cationic dual photocuring or free radical photocuring-cationic thermal curing dual curing. Adding the prepared polyurethane toughening resin to the cycloaliphatic epoxy resin system has the characteristics of effectively improving the elasticity, extensibility and toughness of the system, and the oxetane is a four-membered ring, and the volume shrinkage is small during curing, which can improve the system Adhesion to the base material; at the same time, it can solve the technical defects of light-curing deep-layer curing and heat-curing and sagging in some applications.

The first aspect of the present invention protects a method for preparing a dual-curable polyurethane toughening resin, comprising the following steps:

S1. Take hydroxyl-containing oxetane, hydroxy acrylate, diisocyanate, polymerization inhibitor, and catalyst for mixed reaction to obtain isocyanate semi-blocked composition C, and set aside;

S2. Add macromolecular polyol to composition C and keep it at 60-90° C. for 2-8 hours to obtain dual-curable polyurethane toughening resin.

Preferably, in step S1, the following steps are included:

S11. Firstly mix the hydroxyl-containing oxetane and the hydroxy acrylate in a molar ratio of 1:0.2 to 1:2 to obtain substance A;

S12. Add diisocyanate to substance A according to the molar ratio -NCO:-OH=1:0.95～1:1.05 to obtain substance B;

S13. Add a polymerization inhibitor, a catalyst and the substance B obtained in step S12 to the substance B, mix them uniformly, and maintain the reaction at 40-60° C. for 1-4 hours, so as to obtain the isocyanate semi-blocked composition C;

In step S1, the oxetane containing hydroxyl group includes but not limited to 3-oxetane propanol, 3-oxetane butanol, 3-oxetane methanol, 3-benzene One or more of base-3-hydroxyl-1-oxetane, 3-ethyl-3-oxetanemethanol, 3-methyl-3-hydroxymethyloxetane in any proportion mixture;

In step S1, the hydroxy acrylate is a mixture of one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate and caprolactone acrylate in any proportion.

In step S1, the diisocyanate is hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), toluene diisocyanate (TDI), trimethyl Hexamethylene diisocyanate (TMDI), one or more mixtures of dicyclohexylmethane diisocyanate (HMDI), preferably IPDI, which has higher selectivity and non-yellowing properties.

In step S1, the catalyst is dibutyltin dilaurate or an organic bismuth catalyst, preferably an environmentally friendly organic bismuth catalyst.

In step S1, the polymerization inhibitor is p-hydroxyanisole.

Preferably, in step S2, the macromolecular polyol is added according to the molar ratio of composition C to the reactive groups in the macromolecular polyol -NCO:-OH=1:0.95˜1:1.05.

In step S2, the macromolecular polyol is a polyether polyol synthesized by one of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and methyl tetrahydrofuran, or a polycaprolactone polyol Alcohols, polycaprolactone polyols synthesized by using the above polyether polyols as initiators, hydroxyl-terminated polybutadiene, alkoxyl-terminated polydimethylsiloxane, neopentyl glycol and tetrahydrofuran copolymerized glycol, A mixture of one or more of polytrimethylene ether glycol and UNIPOL-B series liquid polyester polyols in any proportion. The number average molecular weight is between 400 and 6000, preferably between 600 and 2000.

Preferably, in step S1, the quality of the polymerization inhibitor used is 0.01% to 0.5% of the total mass of oxetane containing hydroxyl, acrylate hydroxyester, diisocyanate, and macromolecular polyol; the quality of the catalyst used is oxetane containing hydroxyl 0.01-0.2% of the total mass of cyclobutane, hydroxy acrylate, diisocyanate and macromolecular polyol.

The second aspect of the present invention protects the polyurethane toughened resin prepared by the method described in the first aspect.

The third aspect of the present invention includes the application of the polyurethane toughening resin described in the first aspect in an alicyclic epoxy resin system.

A dual-curable polyurethane toughening resin of the present invention and its preparation method and application have the advantages of:

First, the polyurethane toughening resin of the present invention can be subjected to free radical-cationic dual photocuring or free radical photocuring-cationic thermal curing dual curing;

Second, the cationic curing group of the polyurethane toughening resin of the present invention is oxetane, and oxetane is a four-membered ring, which is easier to ring-open than the three-membered ring of epoxy, which can increase the curing speed and shrink the volume during curing Small, can improve the adhesion of the system to the substrate;

Third, the polyurethane toughening resin of the present invention can be used as the main body, or can be added into epoxy resin as a formula resin to achieve dual curing, that is, the polyurethane toughening resin of the present invention is added to the cycloaliphatic resin in a certain proportion. The epoxy resin system can effectively improve the elasticity, extensibility, and toughness of the system, and the oxetane is a four-membered ring, and the volume shrinkage is small during curing, which can improve the adhesion of the system to the substrate;

Fourth, the addition of the polyurethane toughening resin of the present invention can realize the construction process of free radical photocuring at room temperature and cationic thermosetting molding at high temperature, so as to solve the problem of impenetrable deep curing of photocuring in some applications, and flow of heat curing. hanging problem.

Detailed ways

The following examples are given as specific embodiments of the invention and serve to illustrate the practice and advantages of the invention. It should be understood that these examples are illustrative only and are not intended to limit the specification or the appended claims in any way.

Embodiment one

Preparation of PPG1000-PU

S1. First mix 26.78g of 3-oxetanemethanol with 34.09g of hydroxyethyl acrylate (molar ratio 1:1) to obtain substance A;

Another 135.12 g of isophorone diisocyanate (IPDI) were added to obtain substance B;

Add 0.5 g of the polymerization inhibitor p-hydroxyanisole and 0.5 g of the catalyst dibutyltin dilaurate to the substance B, mix them uniformly, and maintain the reaction at 60 ° C for 2 hours to obtain the isocyanate semi-blocked composition C;

S2. Add 304.01 g of macromolecular polyol polypropylene glycol 2000 (PPG2000, 2-functional) according to the molar ratio of the composition to the reactive group in the macromolecular polyol -NCO:-OH=1:1 and keep it at 70°C for 6 hours to react. The finished product PPG1000-PU can be obtained.

Embodiment two

Preparation of PPG600-PU

S1. First mix 58.75g of 3-methyl-3-hydroxymethyloxetane and 37.43g of hydroxypropyl acrylate (molar ratio 1:0.5) evenly to obtain substance A;

144.96 g of hexamethylene diisocyanate (IPDI) were added to obtain substance B;

Add 0.4g of the polymerization inhibitor p-hydroxyanisole and 0.4g of the catalyst dibutyltin dilaurate to the substance B, mix them uniformly, and then maintain the reaction at 50°C for 3 hours to obtain the isocyanate semi-blocked composition C;

S2. According to the molar ratio of the composition to the reactive group in the macromolecular polyol -NCO:-OH=1:1, add 258.86g macromolecular polyol polyethylene glycol 600 (PEG600, 2 functional) and keep it at 80°C for reaction 4 The finished product PPG600-PU can be obtained within hours.

Embodiment three

Preparation of PTMG1400-PU

S1. First mix 21.21g of 3-oxetanepropanol and 39.49g of hydroxybutyl acrylate (molar ratio 1:1.5) evenly to obtain substance A;

An additional 119.76 g of dicyclohexylmethane diisocyanate (HMDI) was added to obtain substance B;

Add 0.45g of polymerization inhibitor p-hydroxyanisole and 0.45g of catalyst organic bismuth catalyst bismuth neodecanoate to substance B, mix uniformly and maintain 40°C for 4 hours to obtain isocyanate semi-blocked composition C;

S2. According to the molar ratio of the composition to the reactive group in the macromolecular polyol -NCO:-OH=1:1, add 319.54g macromolecular polyol polytetrahydrofuran ether 1400 (PTMG1400, 2 functional) and keep it at 88°C for 3 hours. The finished product PTMG1400-PU can be obtained.

The application effects of the foregoing embodiments of the present invention are as follows:

Four sets of comparative examples were designed as follows, wherein the reagents in each set of comparative examples were measured in mass percentages to obtain corresponding products after mixing, and their elongation was measured (as shown in Table 1 below).

Comparative example 1: 97% 2021P epoxy resin, 3% cationic photoinitiator Easepi 6976;

Comparative example 2: 56% 2021P epoxy resin, 30% PPG1000-PU, 1% photoinitiator 184, 3% cationic photoinitiator Easepi 6976;

Comparative example 3: 56% 2021P epoxy resin, 30% PEG600-PU, 1% photoinitiator 184, 3% cationic photoinitiator Easepi 6976;

Comparative example 4: 56% 2021P epoxy resin, 30% PTMG1400-PU, 1% photoinitiator 184, 3% cationic photoinitiator Easepi 6976;

Table 1

According to the above table 1, it can be seen that the elongation of the corresponding product added with the toughened resin of the present invention is significantly improved, indicating that the toughened resin of the present invention has an obvious effect.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. one kind can the polyurethane toughened resin of dual cure preparation method, it is characterised in that: include the following steps

S1, the oxetanes containing hydroxyl, crylic acid hydroxy ester, diisocyanate, polymerization inhibitor, catalyst hybrid reaction are taken, It is spare to obtain the semiclosed composition C of isocyanates；

S2, addition macromolecular polyol keep 60-90 DEG C of reaction 2-8h into composition C, and i.e. acquisition can dual cure polyurethane Tough resin.

2. preparation method according to claim 1, it is characterised in that: in step S1, include the following steps:

S11, first the ratio of the oxetanes containing hydroxyl and crylic acid hydroxy ester 1:0.2~1:2 in molar ratio mixed it is equal It is even, obtain substance A；

S12, diisocyanate is added into substance A according still further to molar ratio-NCO:-OH=1:0.95~1:1.05 to obtain substance B；

It is uniformly mixed after in S13, the substance B that addition polymerization inhibitor, catalyst are obtained with step S12 into substance B, and maintains 40- 60 DEG C of 1~4h of reaction, to obtain the semiclosed composition C of isocyanates.

3. preparation method according to claim 1, it is characterised in that: in step S1, the oxetanes containing hydroxyl Including but not limited to 3- oxetanes propyl alcohol, 3- oxetanes butanol, 3- oxetane methanol, 3- phenyl -3- hydroxyl - One of 1- oxa- ring, 3- ethyl -3- oxa- fourth ring methanol, 3- methyl -3- hydroxymethyl-oxetane are a variety of by any The mixture of ratio.

4. preparation method according to claim 1, it is characterised in that: in step S1, the crylic acid hydroxy ester is acrylic acid The mixture of one of hydroxyl ethyl ester, hydroxypropyl acrylate, hy-droxybutyl, caprolactone or a variety of arbitrary proportions.

5. preparation method according to claim 1, it is characterised in that: in step S1, the diisocyanate is hexa-methylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), benzene dimethylene diisocyanate (XDI), toluene diisocyanate Acid esters (TDI), trimethyl di-isocyanate (TMDI), one of dicyclohexyl methyl hydride diisocyanate (HMDI) or a variety of Mixture, preferably IPDI have more highly selective and non yellowing.

6. preparation method according to claim 1, it is characterised in that: in step S1, the catalyst is two fourth of tin dilaurate Base tin or organo-bismuth class catalyst；The polymerization inhibitor is p-hydroxyanisole.

7. preparation method according to claim 1, it is characterised in that: in step S2, according to composition C and macromolecular polyol In reactive group molar ratio-NCO:-OH=1:0.95~1:1.05 be added macromolecular polyol.

8. preparation method according to claim 1, it is characterised in that: in step S1, quality used in polymerization inhibitor is containing hydroxyl Oxetanes, crylic acid hydroxy ester, diisocyanate, macromolecular polyol gross mass 0.01~0.5%；Catalyst institute With quality be the oxetanes containing hydroxyl, crylic acid hydroxy ester, diisocyanate, macromolecular polyol gross mass 0.01 ~0.2%.

9. according to claim 1 to the polyurethane toughened resin of 8 any the method preparations.

10. application of the polyurethane toughened resin in cycloaliphatic epoxy resin system according to claim 9.