Pull crowded shape craft basically produces composite material product with a future life, it is a craft with the widest application in composite material course of study. Some closer year come as environmental problem outstanding with each passing day, use pull crowded craft to make successive fiber increase thermoplastic plastic composite material gets increasingly the attention of people.
Although thermoplastic plastic pull crowded shape have stronger flexibility and anti-impact properties, good fight destroy allowance of ability, loss tall, can fill model, can solder, biology consistence is good, can reclaim, when shaping need not solidify reaction, shape it is OK that speed is reached quickly the characteristic such as repeated usage, but heretofore still did not win general commercial application.
The reason depends on this kind of craft getting of the following defect restrict: If fuse-element viscosity is tall, shape temperature tall, matrix presents solid state below room temperature, the shrinkage when need controls refrigeration and fuse-element refrigeration accurately is big, produce character to measure wave motion to wait greatly.
To make thermoplastic of material pull crowded shape application wins wider application, main task is to develop the equalest treatment craft, reduce cost and improve quality.
Because pull crowded craft itself,be a kind can the typical workmanship of serial production composite material of economy, the use that and can realize automation serial production reachs goods is extensive, so this craft already was taken seriously generally in industrial developed country, development rate is very rapid.
If the United States is patent (patent date: US5091036) and Dr.ScottTaylor is right thermoplastic of the research achievement of composite material publish, to thermoplastic composite material is pulled squeeze shaping industrial application to bring revolutionary propulsion.
Wraparound and character, pull from matrix of hot solid sex crowded shape change arrives thermoplastic matrix pulls crowded shape the crucial problem that encounters basically includes: Matrix presents solid state below room temperature, the gender is moved to differ in melt temperature indelicacy (viscosity is tall) wait for a characteristic greatly with the shrinkage when fuse-element is cooling, current, carry out thermoplastic colophony radical of composite material pull crowded shape typical research achievement and its progress can be generalized as follows.
1, manufacturing technology respect
As a result of thermoplastic the viscosity of body of colophony be in harmony is big, macerate difficulty, the crucial point that improves research work consequently is centered in macerate technology respect, and different the essential distinction that draws crowded craft also is on the difference of macerate method and macerate craft.
Normally, according to macerate technology but thermoplastic composite material pulls crowded craft cent to be blame reaction model pull crowded craft and reaction to help crowded technology two kinds big. From at present applied case looks, blame reaction craft takes principal part, application is relatively wide, also mature quite comparatively. Graph 1 be those who use 2 kinds of different kind is thermoplastic composite material draws crowded craft sketch map.
Thermoplastic composite material pulls colophony radical crowded shape the process of craft and characteristic
1.1 blame reaction help crowded technology
1.1.1 fuse-element macerate
Macerate method is to let the even and dispersive, successive fasciculus that increases pulling force beforehand pass commonly a chain of round of department, make fiber sufficient in melt colophony macerate. To raise permeability, still increase constant pressure normally, or quality of small opposite element is the same as interfuse phyletic modified group share (or plasticizer) etc.
This craft already matured quite at present, the fiber when having macerate is twined not easily, and it is OK to can machine everything the advantage of the plastic material that melt flows.
1.1.2 dissolvent macerate
This method is to choose a kind of appropriate dissolvent, also can be the mixture dissolvent that a few kinds of dissolvent match, dissolve colophony completely, make the solution that gets low viscosity, and with this macerate fiber, volatilize solvent next, reclaim make beforehand dip makings. This method was overcome thermoplastic the defect with colophony melt tall viscosity, can well macerate fiber.
This craft also is put in a few inadequacy, be like solvent evaporate and reclaim cost is high, and easy pollution environment; If solvent is cleared not complete, in composite material regular meeting forms bleb and hole.
Use this method to have the composite material of treatment so, in use process its solvent resistance can have a few effects.
1.1.3 pulverous macerate
Technology of pulverous macerate preparation is to be in vulcanization bed, carry electrostatic action adsorption of colophony fine pink the surface at monofilament of the fiber in fasciculus, heat next make pulverous frit knot is in fibrous surface, be in finally shape make fiber is able to infiltrate in the process. Treatment process does not accept the restriction of matrix stickiness, of quality of tall opposite element polymeric can distributing in fiber. Damage of fiber of this kind of craft is little, polymer does not have degradation, have the potential advantage with low cost. Agree with the diameter of tree cosmetics end of this kind of technology with 5~l 0 ìm advisable.
1.1.4 jumbly without twist roving law
This law is will thermoplastic colophony spins fiber or film is taken, the much major general that measures according to containing gum next is certain proportional enhance fiber and colophony fasciculus incorporate cheek by jowl mix gauze, repass a high temperature is sealed macerate area, become colophony fiber frit matrix. The advantage of this law is colophony content is controlled easily, fiber can get sufficient soak.
1.2 reaction help crowded technology
1.2.1 get together beforehand body helps crowded technology
The resin that place of this kind of craft uses is melt heats again after mixing monomer and initator, because get together beforehand put oneself in another's position is initiative and relative molecular quality small, viscosity is low it is good to reach fluidity, make fiber and one of edge soak, react at the same time, can achieve ideal macerate result thereby. This kind of craft asks monomer group rate is rapid, reaction needs to be controlled accurately. What this craft applies to fibre glass, carbon fiber, nylon and other staple to increase is thermoplastic pull plasticly crowded shape, resinous suitable scope is wider. Get together beforehand if the graph is shown 2 times,body helps crowded technological process.
Thermoplastic composite material pulls colophony radical crowded shape the process of craft and characteristic
1.2.2 reaction inject helps crowded technology
With normally pull crowded craft photograph to compare, reaction injects (RIM) the characteristic that helps crowded technology depends on: In helping crowded process, be colophony group share antrum of macerate of direct infuse colophony or pull crowded mould entry point and enhance material macerate, shape through heating mould next, it is to will be pulled actually crowded craft and (R I M) moulding craft union rises, and a kind when form very distinctive craft.
RIM helps crowded process in, colophony system is divided into A, B commonly two groups share, each groups of portion oneself won't react. The A that fastens resinite, B sends colophony to mix unit via metric pump after two groups of portion warm-up, after mixing adequately, guide colophony macerate antrum or macerate of mould entry point enhance material directly, enhance material to also pass warm-up among them, made sure colophony macerate undertakes below the condition of high temperature so, at this moment the viscosity of colophony system is extremely low, be opposite consequently fiber permeability is wonderful; The mixture of colophony group share and use undertake at the same time, the problem of operating period of nonexistent also colophony, because colophony mixes point of entry of unit and adjacent mould, the perhaps presents solid state below normal temperature resinite that because this is possible,uses fast solidify is.
If the graph is shown 3 times,RIM helps crowded technology
Thermoplastic composite material pulls colophony radical crowded shape the process of craft and characteristic
1.2.3 former help crowded technology
This kind helps crowded technology actual as similar as R IM craft. Different is, direct infuse pulls the colophony of online preparation crowded mould.
2, manufacturing facilities respect
Pull crowded equipment photograph to compare with colophony of hot solid sex, thermoplastic colophony pulls crowded need to add a few specific equipment: If macerate stands (powder or fuse-element chamfer) , tailor-made mould and refrigeration paragraph. Thermoplastic colophony reactivity is pulled crowded in reaching blame reactivity to pull the pulverous macerate in squeezing and fuse-element to help crowded technology, still need to undertake warm-up to enhancing fiber (if pursue,4 are shown) .
Foreign University Of Ghent, department Of Textiles is designed recently and open those who gave out a complete set of to be used at thermoplastic plastic fiber increases pull jam shaping product line, add among them add shrinkage fitting buy to be able to rise effectively beforehand enhance fiber and colophony dispersive function, and fuse-element viscosity, enhance fiber amount, material the payoff that the parameter such as the size of original temperature and traction is the length that adds shrinkage fitting buy beforehand and temperature.
Graph 4 those who improve is thermoplastic colophony draws sketch map of crowded production technological process
2.1 thermoplastic plastic the as plastic as hot solid sex contrast that draws crowded tooling
(1) sex of data side hot solid is plastic pull crowded: Enhance fiber and colophony to mix in helping crowded process through macerate chamfer even; Thermoplastic plastic pull crowded: With had undertaken ahead of schedule beforehand the fiber of macerate and colophony undertake pulling squeezing directly.
(2) sex of mould respect hot solid is plastic pull crowded: Pass in the mould heat solidify; Thermoplastic plastic pull crowded: Cooling solidify is passed in the mould, and have in the mould add shrinkage fitting buy, make sure fiber and colophony are dispersive and even.
2.2 thermoplastic plastic the characteristic that pulls crowded mould
Thermoplastic plastic the core component that pulling crowded mould is whole product line. Goods sclerosis, shape and the technology measure such as refrigeration passes pressure and temperature to deliver inside the mould undertake. Right thermoplastic plastic the demand that draws crowded mould results from commonly plastic to heating up solid sex the main demand that draws crowded mould, like surface of antrum of better wearability, model Gao Guangjie is spent, sex of dimension stability, easy operation and divisional temperature control. These targets can pass the following method to achieve at present: Design of steel of use plating chromic tool, double deck and report heating element.
Ask normally mould model antrum should polishing and plating hard chromium, mould hardness should amount to HRC70, surface roughness Rz<0.4. The length of sclerotic area depends on vulcanize countervail process or indispensible curing time. According to document report, mould sclerosis area but from 50, 500 differ to 1000mm.
Already had research proof, from the 300 moulds to 500mm length can gift help appearance of crowded profile first-rate and mechanical performance.
Normally thermoplastic pull space of crowded mould a person operating from within in coordination with outside forces to become different temperature division (like the graph 5 are shown) , its basically are divided to heat with refrigeration two parts. Heating is to make sure fiber and colophony distributing equably partly, heat longerly Duan Ke makes with assuring to generate enough pressure colophony / sufficient flow mixes Bo fine, and cooling part is to mix the dimension stability that assures a product. This kind of hot segregation can assure to there is appropriate temperature gradient on mould length direction, the core rod that can use different diameter will get used to the different contractility of different fuse-element.
Graph 5 thermoplastic colophony draws sketch map of crowded mould structure
Thermoplastic of colophony radical pull crowded shape to had entered practical phase in abroad, and still be in an abecedarian to explore applied phase in our country, should accelerate this to shape development application of the technology, the key is nodded even if should master the right choice that enhances fibrous macerate and craft parameter adequately, and the stability that ability increases manufacturing facilities.