CN1139398A - Method and apparatus for resin impregnated porous mesh - Google Patents

Abstract

A method and apparatus for impregnating a porous web with a thermosetting resin is disclosed. The method comprises using a resin coating apparatus having a rotating roll (4) on which a thermosetting resin in substantially uncured liquid form is deposited; passing the porous web in countercurrent contact with the thermosetting resin so that the thermosetting resin is transferred to the porous web; exposing the resin-containing porous substrate to an elevated temperature below that which remains partially cured; and passing the resin-containing web through a heating zone to partially cure the resin and form a prepreg member. The process is particularly useful for coating solventless resin formulations onto glass fiber webs for making prepregs for electrical laminates. The apparatus comprises a resin coating device having a rotating roller (4); means for applying a thermosetting resin in liquid form to the rotating roll; means for feeding the web (2) in a direction opposite to the direction of rotation of the roll and into contact with the thermosetting resin thereon and then to a resin curing station; and means for heating the resin-containing substrate between the rotating roll and the resin curing station (14).

Description

The method and apparatus of resin dipping porous net

The present invention relates to thermosetting resin dipping porous net.In specific embodiment, the present invention relates to method and apparatus with solvent-free aathermoset resin system impregnated glass fiber base material.

The manufacturing of cured thermosetting circuit board substrate starts from liquid thermosetting resin system impregnated glass fiber base material.Then " preimpregnation materials and parts " are made in the base material part curing of resin dipping.The preimpregnation materials and parts of one group of stratiform are depressed heating adding, resin is solidified fully and make hard laminate, it is as the substrate of circuit board.

Though existing various thermosetting resins, as at room temperature being the low-molecular-weight epoxy resin of liquid, but now circuit board requires to use at room temperature the high performance resin system as solid or thick liquid, and with resin to be coated on the base material in fusion form or the solution form.But the processing thermosetting resin is difficult under molten condition, because make the required high temperature of resin fusion can make the resin premature setting, makes resin poor to " infiltration " of base material, i.e. saturation deficit.

The commercial run that is used to make the preimpregnation materials and parts now be organic solution with resin with resin-coating to base material.Solwution method must comprise such one usually with the partly solidified step of carrying out of resin, in this step,, solvent is removed from the preimpregnation materials and parts by solvent is heated to volatilization temperature.But this method has many shortcomings: at first, it need handle or discharge organic volatile.Secondly, solvent volatilizees from uncured resin and may produce cavity and inhomogeneities in the preimpregnation materials and parts and then in the laminate that solidifies.In addition, remove solvent step and need a large amount of time.

Having proposed a kind of method, to be used for that solventfree resin is coated to glass fibre online, this method comprise with solventfree resin deposit to the rotation roller on, and make reverse contact of the glass fiber mesh and the resin of deposition pass through the rotation roller so that resin transfer is moving online, then through optional second applicator roll that resin-coating is arrived the reverse side of net, deliver to bringing-up section, make resin partly solidified.This method is open in EP476752.Hope is removed second applicator roll under the condition of not damaging product appearance and quality.

So, the purpose of this invention is to provide a kind of method and apparatus with thermosetting resin impregnation of fibers base material.One concrete aspect, the purpose of this invention is to provide the method for simplifying and the cheap apparatus of the solvent-free aathermoset resin system impregnated glass fiber of a kind of usefulness base material.

So, the present invention relates to a kind of method of flooding the porous net with thermosetting resin by following steps, uncured liquid form thermosetting resin is deposited on the rotation roller; Make the porous net with described roller on the reverse mode that contacts of described resin pass through so that thermosetting resin is transferred on the porous substrate; Make the porous base that contains resin just by the section of being heating and curing, make resin partly solidified.In the method, resiniferous porous substrate is exposed to greater than 100 ℃ under the high temperature less than this curings section maximum temperature earlier by solidifying before the section.

In exemplary embodiments of the present invention, a kind of like this method with thermosetting resin dipping porous net is provided, this method comprises: the resin-coating equipment that provides the rotation roller; The liquid form thermosetting resin prescription that will contain uncured basically thermosetting resin deposits on the rotation roller; Make the porous net to pass through, so that the thermosetting resin prescription is transferred on the porous substrate with the thermosetting resin of rotation on the roller reverse mode that contacts of filling a prescription; Resiniferous fiber base material is exposed at least 100 ℃ to the high temperature less than the maximum temperature of solidifying section; And make resiniferous fiber base material by solidifying section, make resin partly solidified and make the preimpregnation materials and parts that contain fiber base material and partly solidified thermosetting resin.

According to the present invention, also provide a kind of and flood the device that the porous net prepares the preimpregnation materials and parts with thermosetting resin, this device includes the resin-coating equipment of rotation roller; Make the thermosetting resin of liquid form deposit to the equipment that rotates on the roller; Become reverse with the direction of motion and the porous net is fed to the rotation roller and contacts, be fed to the equipment of resin solidification section then with thermosetting resin on it with respect to the rotation roller; And the firing equipment between rotation roller and described resin solidification section.

The present invention is for providing a kind of technology of suitable simple and inexpensive with the thermosetting resin impregnation of fibers base material of liquid form.This method is particularly suitable for preparing the preimpregnation materials and parts that finally are used for electrical laminated plate with solventfree resin system impregnated glass fiber net.The purpose of resin-coating method of the present invention is the abundant infiltration that reaches base material, so that does not use second applicator roll to make resin-coating arrive the reverse side of base material, from but make high-quality cured layer pressing plate more economically.

In resin-coating method of the present invention, with the hot solids thermoplastic resin-impregnated fibers base material of liquid form.Though the inventive method useable solvents base resin is implemented, for method of the present invention, preferred resin system is the resin system that does not contain organic solvent, as water-based resin system or solventfree resin system.For the solventfree resin system, can at room temperature there be low viscous thermosetting resin to reach liquid form by using, perhaps thermosetting resin is heated to such temperature, reach the abundant just enough low viscosity of base of soaking into.Certainly be that under one situation of back, resin system (thermosetting resin and any curing component that uses with it) must be without any the curing of significance degree in the time range of base material dipping process under its melt temperature.

Can be with reference to figure 1 explanation resin-coating method of the present invention and device, base material 2 (is generally any short fiber, felt or woven porous material, be preferably woven glass fiber mesh) to send to from conveying equipment 1, conveying equipment generally includes and be used for automatic equipment that net is sent under selected speed and institute's network selection tension force.Fleece can be chosen wantonly by for example infrared heater heating before being fed to the resin-coating section.Guide device 3 is installed makes net be sent to resin-coating roller 4 with certain contact angle α radian.Angle α can be with the total structural change of coating scheme, changes usually in 30-180 degree scope, and preferred 90-150 degree, 120-150 degree most preferably, so that make resin waste minimum, and that the heat from the roller to the base material is transmitted is maximum.Rotation roller 4 is delivered to liquid resin film 5 basal plane of the reverse net that passes through 2.Applicator roll 4 remains under such temperature, and resin molding 5 is remained under the liquid form that does not solidify basically.This temperature changes with resin, but usually in 50-250 ℃ of scope, preferred 100-200 ℃.The speed that tension force when making rotary speed, the net 2 contact pressure resin films 5 of applicator roll 4 and net 2 are fed to applicator roll is coordinated mutually, so that make Wondertek arrive good infiltration.These specification requirements can be with the variations such as heating efficiency of resin system, net materials type and B-staging unit, downstream.Usually, the rotary speed of applicator roll 4 in 70160% scope of network speed, the 100-140% of preferred network speed; The tension force of net 2 usually in 0.4536-1.3608kg (1-3 pound)/2.540cm (liner inch) scope, preferred 0.6804-0.9072kg/2.540cm (1.5-2.0PLI); And the feed rate of resin-coating section is crossed in 0.04064-1.016m/s (8-200ft/min) scope by Netcom, preferred 0.127-0.635m/s (the about 125ft/min of 25-).

By the resin delivery device that is shown nozzle 7 here resin molding 5 is coated on the applicator roll 4, nozzle 7 can be coated to the liquid resin of controlled amounts on the surface of revolution of applicator roll.Nozzle 7 can carry the equipment of the resin of liquid form to link to each other in room temperature or under heating up with any continuously.To under different volumetric rate, carry out resin transfer, synchronous with the speed of mobile network, so that, make the time of staying in the resin transfer system the shortest simultaneously with the resin transfer of predetermined on the net.Resin delivery device for example can comprise static mixing machine, the dynamic mixer that the outlet of temperature control links to each other with nozzle 7 or mix squeezer.

Use measuring equipment with resin delivery device 7, so that control is transported to the quantity of online liquid resin, measuring equipment here is shown decides crack roller 8 between the contact point that is installed in nozzle 7 and resin molding 5 and sends net to.Decide crack roller 8 and be preferably one and roller than minor diameter arranged than applicator roll 4, with respect to the applicator roll counter-rotating, its rotary speed in network speed 1-50% scope, preferred 8-35%.Optional scraper plate 10 can be installed, to prevent that resin from refluxing from coated side, by with the pitch deposition face with decide the crack roller and install forward with respect to applicator roll 4, promptly with the angle β of horizontal radius less than 90 °, so that prevent that by gravity resin from counterclockwise flowing down also and can reach such result from being coated with roller.The slit of deciding between crack roller 8 and the applicator roll 4 by careful setting under first kind of situation that is controlled at of resin-coating speed on the net reaches, to obtain uniform thickness.Secondly, the rotary speed of applicator roll matches with network speed, with resin molding is transferred to mobile on the net.In addition, because do not need film-traying roll to control contacting of mobile net and applicator roll, therefore need control net tension force to guarantee the stable operation of resin-coating process.

Optional resin is removed equipment 9 (scraper plate shown here) and is used for removing at resin molding 5 and sending between the net 2 after the contact from applicator roll, such cull by before 360 ° of rotations of roller on roller residual any resin.Resin is removed equipment and is preferably mounted at roller and the porous net place that sends to, thus at net with before applicator roll contacts, make that directly to deposit to porous from any resin that contacts with scraper plate online.

Resiniferous net 6 is fed to by bringing-up section 11 and solidifies section 14, is subjected to the thermal source effect at the resiniferous net of bringing-up section, is shown infrared heater 13 here.Thermal source reduces to minimum most preferably near the resin-coating face so that make from the online heat loss of resin dipping.Heating steps impels resin to flow in net or by net in the middle of this, also can increase mobile by the net of resin pickup and vertical direction are 45 ° at the most (preferably 20-40 °).

The common available Fig. 2 of prepreg process of the present invention describes.The Autonet that fleece 43 usefulness are fit to is sent system 42 to and is transported to resin-coating section 44, and this system has the measurement device of control feed rate and net tension force.The net tension control apparatus is known in this specialty.For example, separating winding up roller 41 can have lock with front end dancer rools combination, and its keeps intending going into to be in the predetermined net tension force into the unit of leading between dancer rools and the resin-coating section.Equally, can keep the downstream net tension force that is fit to by the dancer rools that the speed that makes the variable-ratio that is in the bringing-up section downstream decide the diameter roller is slowed down.

Fleece is sent to by resin-coating section 44, and here the resin-coating segment table is shown and is vertically oriented, and wherein when liquid resin applied with the method that describes in detail above, net passed through by controlled speed with usually up direction.Coated segment 44 comprises resin delivery device, the blender that has resin to mix with curing system remains on required temperature control of required viscosity and as heat loss and the thermal source that flow of raising resin by netting that is used to reduce from the net of impregnating resin described herein with resin system.Optional minor diameter conditioning roller can be used to promote after the resin-coating and infiltrate net before solidifying.

The net 45 that resin is saturated is fed to from the resin-coating section and solidifies section 46, and wherein the Netcom that resin is saturated crosses to be exposed in thermal source such as convection furnace or the infrared heater and heats, and resin is solidified in the situation lower part of not gelling, and this process is called " B-staging ".The temperature of the bringing-up section before solidifying section is usually less than in certain system solidifies the temperature that section is kept, and is at least 100 ℃ usually, and preferred 100-200 ℃, most preferably 130-160 ℃.(because the heat loss between thermal source and the resiniferous net, thermal source itself can be operated being higher than under the given temperature of bringing-up section).The temperature of solidifying section changes with resin system and required resin solidification degree, but usually in 120-250 ℃ of scope, preferred 150-230 ℃.The net that resin is saturated will be subjected to being enough to reaching the B-staging of required state of cure time and handle, and 15% curable groups such as epoxy radicals are solidified, and preferably at the most 10%, more preferably at the most 5%, the time is generally 10s to 8min.Net is sent to from resin solidification section 46 with the form of preimpregnation materials and parts 47, and twists on the draw roll 48, so that store, can directly send in lamination on the other hand.

By being handled to make resin solidification and make the preimpregnation materials and parts force together into laminar structure, one group of stratiform preimpregnation materials and parts makes laminate.Laminate can have been chosen one or more layers conductive material such as copper wantonly.Lamination is generally time 30min to 4hr, preferred 1-2hr, temperature 160-300 ℃, preferred 170-200 ℃, pressure 3.516-35.16kgf/cm ²(50-500psi).Laminate can choose that heating 1-6hr comes " solidify the back " under 200-230 ℃, normal pressure wantonly, to improve hot property.

The lamination composition that contains epoxy resin will contain curing agent.The effective curing agent that becomes known for epoxy resin for example comprises amine, acids, anhydrides, phenols and imidazoles.Also referring to EP476752.At present the preferred consolidation agent of best lamination performance is provided is the phenol degree of functionality greater than 1.75 phenolic compounds for epoxy composite.Preferred phenol curing agent is to react the phenolic aldehyde that makes by dihydric phenol such as resorcinol or bisphenol-A and formaldehyde in acid solution to dye clearly.The preferred clear colorable resin curing agent of phenolic aldehyde is that bisphenol-A dyes clearly, and its each phenolic group heavily be 60-500, and preferred 60-300, each molecule be on average greater than 2 phenolic hydroxyl groups, preferably 3-5 phenolic hydroxyl group.Such phenol dyes clearly and can buy from Shell International Chemical Company by trade name EPIKURE DX-175 (EPIKURE is a trade mark).Phenol dyes the quantity of curing agent in composition clearly should make epoxy resin cure, usually whenever amount epoxy resin has stoichiometry 0.75-1.25 equivalent phenol to dye curing agent clearly.Percentage is by weight pressed total restatement of epoxy resin and curing agent, and the consumption of curing agent is generally 10-70% (weight), preferred 15-50% (weight), most preferably 15-40% (weight).For fire-retardant application, curing agent can be the mixture of the phenolic curing agent of phenolic resin curative and bromination.In order to accelerate in the composition the faster curing of resin Composition and/or more to solidify under the low temperature, can use optional curing accelerator.

Aathermoset resin system must design in some specification requirement scope of resin-coating procedure parameter requirement.Resin formula does not make to the base material under the temperature of resin solidification in resin-coating in required time must be liquid.Resin system must have enough low viscosity, makes Wondertek arrive good infiltration or saturated, and does not use film-traying roll in application point.But in case resin system is coated on the base material, it just must have sufficiently high viscosity, and it is dripped from network in that resiniferous Wondertek is unlikely before the bringing-up section.Viscosity is in 0.05-1.0PaS (0.5-10P) scope, and the resin formula of preferred 0.05-0.6PaS (0.5-6P) is best suited for.At present preferred resin system be have WPE be the bisphenol-A of 175-190 diglycidyl ether, WPE is arranged is the diglycidyl ether, the mixture that phenolic aldehyde dyes curing agent and glyoxal ethyline accelerator clearly of bromination of the bisphenol-A of 310-350 and bromine content 30-50%.

Method of the present invention can be chosen wantonly with such thermosetting resin prescription and implement: it contains organic solvent or diluent, and its quantity can effectively reduce the viscosity of system, so that processing.Polar organic solvent is to be fit to as ketone, alcohols and glycol ether.The boiling point of selected solvent is usually less than 160 ℃.For epoxy resin, preferred solvent is ketone such as acetone, MEK and methyl iso-butyl ketone (MIBK), and the solvent mixture of they and alkylene glycol ether such as propylene glycol monomethyl ether.The ratio of solid constituent can have bigger variation in composition, depends on the quantity of other components and the application of composition, but the solvent in solvent substrate system accounts for the 15-50% (weight) of prescription total amount usually.

Embodiment 1

Carried out an experiment with method of the present invention; To estimate between resin-coating and the partly solidified step of prepreg process, the base material of resin dipping is exposed to the influence in the infra-red heat.To be coated to the glass fiber mesh of wide 1.27m (50 ") based on the solventfree resin system of the diglycidyl ether of bisphenol-A, and use usually applicator roll structure as shown in Figure 1, the net contact angle is 135 °, and the applicator roll temperature is 127 ℃.The back side of the net of resin dipping is by remaining on the infrared heater under 370 ℃, from the center 7.62cm of 30.48cm * 30.38cm (12 " * 12 ") infrared heater (3 ").Wang center directly is exposed in the infra-red heat like this, simultaneously Wang seamed edge (the about 45.72cm in every limit (18 ")) directly be not exposed to and pine for.The infrared heated side (1.27m (50 ") of net) then by and be in 149 ℃ last polishing roll with 3.81cm (1.5 ") (diameter) and contact.Observational network is found, is exposed to the face flash of light of infra-red heat, and that the seamed edge of net be it seems is unglazed, and this point explanation has required bigger osmosis at infrared exposure district resin.

Claims (9)

1. A method of impregnating a porous web with a thermosetting resin by: depositing an uncured liquid form of the thermosetting resin onto a rotating roll; passing the porous web in reverse contact with said resin on said rotating roll so that Transfer of a thermosetting resin onto a porous web; partial curing of the resin by passing a resin-containing porous substrate through a heated curing section, in which the resin-containing porous substrate is exposed to temperatures greater than 100°C and below said curing temperature before passing through the curing section. Segments maintained at high temperatures between the maximum temperatures. 2. The method according to claim 1, wherein the high temperature is maintained in the temperature range of 100-200°C, and the curing section is maintained in the temperature range of 120-250°C. 3. A method according to claim 1 or 2, wherein the elevated temperature is provided by at least one infrared heater. 4. The method according to claim 1, wherein the porous substrate is a fiberglass mesh. 5. The method according to claim 1, wherein the thermosetting resin is an epoxy resin. 6. A device for impregnating a porous net with a thermosetting resin, the device comprising: (a) rotating rollers; (b) an apparatus for depositing a controlled amount of a thermosetting resin in liquid form onto said rotating roll; (c) feeding the porous web into reverse contact with the thermosetting resin on said rotating rolls and then through a device for heating and curing; (d) Heating equipment installed behind the rotating rollers and between the curing section. 7. The apparatus of claim 6, wherein said heating means is at least one infrared heater. 8. The apparatus of claim 6, wherein said heating means is mounted in close proximity to said rotating roll. 9. The apparatus of claim 6, wherein said liquid form thermosetting resin deposition means is a nozzle operatively connected to a dynamic mixer.