CN103059277A - Low-viscosity super-leveling polyester resin and synthetic method thereof - Google Patents

Abstract

The invention relates to low-viscosity super-leveling polyester resin and a synthetic method thereof. The low-viscosity super-leveling polyester resin comprises the following raw materials of polyester chips, xylene, trimellitic anhydride and a catalyst. A preparation method comprises the following steps of performing an ester exchange reaction on the trimellitic anhydride and alcoholic hydroxyl groups brought by the polyester chips under the action of heating and the catalyst, and thus obtaining the low-viscosity carboxyl polyester resin. The polyester resin prepared by the preparation method is mainly used as a raw material of powder coating and is prepared into thermosetting powder coating after being mixed and stirred with epoxy resin and other materials, melted, mixed, sheeted, crushed and filtered. A coating film formed by spraying the low-viscosity super-leveling polyester resin has good leveling performance and decorative performance; particularly, and the polyester chips are wide in sources and low in cost, so that the production cost is greatly saved, and the low-viscosity super-leveling polyester resin can be applied to new fields.

Description

The super levelling vibrin of a kind of low viscosity and synthetic method thereof

Technical field

The invention belongs to chemical field, it is synthetic to relate to polyester, the super levelling vibrin of especially a kind of low viscosity and synthetic method thereof.

Background technology

Along with the raising of people's aesthetic conceptions, market is more and more higher to the requirement of powder coating appearance of film.Want to reach a kind of effect of super levelling, must have corresponding material to guarantee.Except selecting first-class flow agent, optical brightener, defoamer, also must there be first-class resin to satisfy.

The vibrin viscosity of general manufacturer production is at 80-90mPa.s (175 °), have in addition up to 130mPa.s (175 °), second-order transition temperature (Tg value) is about 55 °; And to satisfy the effect of super levelling, need 60mPa.s (175 °), even more low viscous vibrin, reduced viscosity generally speaking, second-order transition temperature also and then reduces, and can produce caking phenomenon in summer when serious, and the stable storing of the powder coating of making is descended, therefore, viscosity in 60mPa.s (175 °), second-order transition temperature (Tg value) at 50 °--60 ° and non-caking vibrin become the target that each vibrin producer is pursued.

Polyester slice was not for the powder coating industry originally, but be born in the industries such as producd fibers, Plastic Bottle, cheap and draw materials conveniently, can greatly reduce the production cost of powder coating with polyester slice synthesizing polyester resin, improve simultaneously the physical and chemical performance of powder coating, have good economic worth and social value.

By the publication literature search, find following two pieces of publication documents:

1, nano composite polyester resin of a kind of high-solid lower-viscosity and preparation method thereof (CN1635025), adopt the silicon dioxide gel of the particle diameter 10-150nm of surface band hydroxyl, with the nano silicon composite polyester resin that adopts melting situ aggregation method synthetic molecular weight 1000-5000, hydroxyl value 80-200mgKOH/g, solid content greater than the high-solid lower-viscosity of 95wt%, viscosity 800-2000mPa.s after polyvalent alcohol, the di-carboxylic acid blend, the nanometer titanium dioxide silicone content is 1～15wt% of nano silicon composite polyester resin amount.High-solid level, low viscosity, the list that adopts preparation method provided by the invention to obtain disperses, the nano silicon composite polyester resin of high silicon dioxide concentration, can be used as the raw material of coated material.

2, a kind of bi-component flame-retardant low viscosity unsaturated polyester resin and preparation method thereof (CN102181014A), polycondensation by dibasic alcohol and diprotic acid/acid anhydrides prepares, in reaction, reach the reduction resin viscosity by adding linking agent, fire retardant, improve the strength of materials and fire-retardant purpose, so that this unsaturated polyester resin can be as the breaking surrounding rock of the underground workss such as colliery and the slip casting strengthening material of loose coal rock mass.

By the technical characterictic contrast, above-mentioned two pieces of publication documents are not identical with present patent application.

Summary of the invention

The object of the invention is to overcome the situation of polyester components levelling deficiency in the existing powder coating, the super levelling vibrin of a kind of low viscosity and synthetic method thereof are provided, this vibrin is synthesized by esterification by polyester slice and acid anhydrides makes powder coating, and made powder coating has splendid flow leveling and good mechanical property.

The technical solution adopted for the present invention to solve the technical problems is:

The super levelling vibrin of a kind of low viscosity, its raw material consists of and parts by weight are respectively:

And described polyester slice is terephthalate or DOPCP.

And described trimellitic acid 1,2-anhydride is the technical grade trimellitic acid 1,2-anhydride.

And described catalyzer is experiment level Dibutyltin oxide.

And described xylene solvent is commercially available technical grade chemical purity solvent.

The synthetic method of the super levelling vibrin of a kind of low viscosity, step is: ⑴ in the molten-bath of being furnished with agitator, fractional column, water separator and nitrogen inlet under the vacuum holding attitude suction xylene solvent, and the 25-35% of adding polyester slice total amount, and the startup agitator, slowly heat up simultaneously, and be filled with nitrogen protection from the reactor bottom, treat to rise in the still 160 when spending, whole meltings of cutting into slices, constant temperature are also taken out negative pressure and are reclaimed xylene solvent, stop simultaneously inflated with nitrogen; Take out negative pressure 0.8-0.9Mpa and keep half an hour, observe when the molten distillment of non-xylol flows out in the visor, prove to reclaim and finish; Vacuum breaker adds polyester slice simultaneously in batches, continues melting, makes the gross weight of material in the molten-bath be increased to the 1000-1800 kilogram, holding temperature and inflated with nitrogen protection;

⑵ continue to be filled with molten-bath with nitrogen, be forced into 0.2MPa so that melts is depressed into reaction kettle of the esterification, all do not shift, keep 25-35% melting section the to be continued usefulness of melts total amount, melts is warmed up to 200 ℃-220 ℃ in the reaction kettle of the esterification under stirring state, adds trimellitic acid 1,2-anhydride, and adding Dibutyltin oxide catalyzer, take out negative pressure degree of keeping vacuum tightness 0.9Pa-0.8Pa dehydration, be incubated one hour and keep esterification, obtain the vibrin that acid number is 30--45mgKOH/g;

⑶ withdraw from last vacuum, cools to 170 ℃, and blowing is given as security the sheet packing and got final product.

Advantage of the present invention and positively effect are:

1, to adopt cheap polyester slice be raw material in the present invention, and building-up process is without industrial triwaste pollution, and the building-up process semi-linkage is fit to uninterrupted production in enormous quantities; Do not lump for accomplishing low viscosity, adopted the way that reduces vacuum tightness to make esterification reaction temperature drop to 200 ° of C from 250 ° of C, greatly reduce the generation of condition of high temperature side reaction, make molecular weight more even, it is linear that molecule more tends to, and reduces to greatest extent branched chain reaction, do not make to generate the build molecule, thereby reduced viscosity, reached super levelling effect.

2, the present invention adopts a step esterification, use the trimellitic acid 1,2-anhydride end-blocking, synthetic vibrin has lower melting viscosity and relatively high second-order transition temperature, by collocation can obtain the good coating of surface effect with Resins, epoxy, and has good mechanical property.

The second-order transition temperature of the vibrin that 3, the present invention synthesized is at 50 °--and 60 °, can make powder coating that better storage characteristics is arranged, especially avoided the phenomenon generation of powder coating at the caking in summer.

Embodiment

The invention will be further described below by specific embodiment, and following examples are descriptive, is not determinate, can not limit protection scope of the present invention with this.

The super levelling vibrin of a kind of low viscosity, its raw material consists of component and parts by weight are respectively:

A kind of synthetic method of low-viscosity polyester resin, step is:

The first step: the continuous working system of semi-linkage

In the molten-bath of being furnished with agitator, fractional column, water separator and nitrogen inlet, suction xylene solvent 300kg under the vacuum holding attitude, add the polyester slice of 300kg-500kg and start agitator, slowly heat up simultaneously, and bottom reactor, be filled with nitrogen protection (belonging to the normal pressure protection), to drive a small amount of air in the reactor, prevent oxidation stain; When treating that temperature in the kettle rises to the 160 degree left and right sides, whole meltings of cutting into slices, constant temperature is also taken out negative pressure and is reclaimed xylene solvent, stops simultaneously inflated with nitrogen.

Take out negative pressure 0.8-0.9Mpa and keep half an hour, observe when the molten distillment of non-xylol flows out in the visor, prove to reclaim and finish; Vacuum breaker adds polyester slice simultaneously at twice, continues melting, makes the gross weight of material in the molten-bath be increased to the 1000----1800 kilogram, holding temperature and inflated with nitrogen protection.The benefit of this melting polyester section is not can coking in reactor, can make the preferably melting of cutting into slices, for the product of making high-quality provides possibility.

Second step: esterification

Nitrogen is continued to be filled with molten-bath, be forced into 0.2MPa melts is depressed into reaction kettle of the esterification, all do not shift, keeping the melting section to be continued of 300-500 kilogram uses, material is warmed up to 200 ℃ in the reaction kettle of the esterification under stirring state--and 220 ℃, add trimellitic acid 1,2-anhydride 80---200kg(Shanghai Sheng and reach prosperous Chemical Manufacture), and adding Dibutyltin oxide catalyzer (Nantong Ai De Chemical Manufacture) 5--8kg, take out negative pressure degree of keeping vacuum tightness 0.9Pa-0.8Pa dehydration, be incubated one hour and keep esterification, obtain the vibrin that acid number is 30--45mgKOH/g.

The 3rd step: withdraw from last vacuum, cool to 170 ℃, blowing is given as security the sheet packing and is got final product.

The Tg=50 of gained polyester °--60 °, viscosity: 58-63mPa.s (175 °).

Technical indicator: 1), outward appearance: white or light yellow transparent solid;

2), solid content: 〉=99.5%;

3), softening temperature: 90 °--105 °

4), viscosity: 58-63mPa.s (175 °)

Practical application effect:

In our powder coating factory of company practical application, this polyester property is excellent through in this year, and really very useful on the flow leveling of filming, coating is bright and clean full, meets project demand, obtains client's approval.

Claims (6)

1. super levelling vibrin of low viscosity is characterized in that: its raw material consists of and parts by weight are respectively:

2. the super levelling vibrin of low viscosity according to claim 1, it is characterized in that: described polyester slice is terephthalate or DOPCP.

3. the super levelling vibrin of low viscosity according to claim 1, it is characterized in that: described trimellitic acid 1,2-anhydride is the technical grade trimellitic acid 1,2-anhydride.

4. the super levelling vibrin of low viscosity according to claim 1 is characterized in that: described catalyzer is an experiment level Dibutyltin oxide.

5. the super levelling vibrin of low viscosity according to claim 1, it is characterized in that: described xylene solvent is commercially available technical grade chemical purity solvent.

6. the synthetic method of the super levelling vibrin of low viscosity as claimed in claim 1, it is characterized in that: step is:

In the molten-bath of being furnished with agitator, fractional column, water separator and nitrogen inlet under the vacuum holding attitude suction xylene solvent, and the 25-35% of adding polyester slice total amount, and startup agitator, slowly heat up simultaneously, and be filled with nitrogen protection from reactor bottom, treat to rise in the still 160 when spending, whole meltings of cutting into slices, constant temperature is also taken out negative pressure and is reclaimed xylene solvent, stops simultaneously inflated with nitrogen; Take out negative pressure 0.8-0.9Mpa and keep half an hour, observe when the molten distillment of non-xylol flows out in the visor, prove to reclaim and finish; Vacuum breaker adds polyester slice simultaneously in batches, continues melting, makes the gross weight of material in the molten-bath be increased to the 1000-1800 kilogram, holding temperature and inflated with nitrogen protection;

⑵ continue to be filled with molten-bath with nitrogen, be forced into 0.2MPa so that melts is depressed into reaction kettle of the esterification, all do not shift, keep 25-35% melting section the to be continued usefulness of melts total amount, melts is warmed up to 200 ℃-220 ℃ in the reaction kettle of the esterification under stirring state, adds trimellitic acid 1,2-anhydride, and adding Dibutyltin oxide catalyzer, take out negative pressure degree of keeping vacuum tightness 0.9Pa-0.8Pa dehydration, be incubated one hour and keep esterification, obtain the vibrin that acid number is 30--45mgKOH/g;

⑶ withdraw from last vacuum, cools to 170 ℃, and blowing is given as security the sheet packing and got final product.