CA1083938A

CA1083938A - Process for the manufacture of fiber reinforced laminates

Info

Publication number: CA1083938A
Application number: CA263,386A
Authority: CA
Inventors: Julius Krick; Gustav Bihlmayer; Peter Schnell
Original assignee: Chemie Linz AG
Current assignee: Patheon Austria GmbH and Co KG
Priority date: 1975-11-24
Filing date: 1976-10-14
Publication date: 1980-08-19
Also published as: CH605123A5; DE2552688C2; SE7612731L; IT1071512B; FR2332129A1; SE435154B; NO148285B; NO763524L; FI763035A; NO148285C; FR2332129B1; DE2552688A1

Abstract

ABSTRACT OF THE DISCLOSURE
Process for the manufacture of laminates from a synthetic resin impregnated, fiber-reinforced base ply and ab-sorbent outer plies, in which the absorbent outer ply or plies are pressed onto the base ply, which has a resin content of 40-70% by weight with a flow of between 10 and 60% at 5 kp/cm2 and 150°C, whereby the ply or plies of absorbent material are com-pletely impregnated by the resin available from the base ply, and all plies are joined to one another and fully cured. These laminates are especially useful as a ski component.

Description

1~8~3~3 1 The present invention relates to a process for the manufacture of laminates from a synthetic resin-impregnated, fiber-reinforced base ply and one or two absorbent outer plies.
These laminates can be used with advantage as a ski component, especially as a ski component which is an outer ply of the ski and must therefore have a completely smooth and possibly decora-tive surface.
In the manufacture of ski components which serve, in - the ski, both as an upper boom and/or lower boom, and as an abrasion-resistan-t decorative outer surface, various processes are used. On the one hand, such components are obtained by gluing fiber-reinforced laminates to various thermoplastic films or decorative laminate sheets, whilst on the other hand the fiber-reinforced laminate ply in the pre-impregnated state (B-state or prepreg) can be joined to pre-impregnated, non-reinforced, carrier plies based on resin-impregnated papers or fleeces, thereby giving a laminated material OL high mechanical strength, possessing a resin-rich, possibly decorative, and abrasion-resistant surface. ;
Similar products are obtained by processing the stated plies and 20 - resins by a wet pressing process~
Thus, for example, Austrian Patent Specification 313,129 discloses a ski component in which an outer ply, impregnated with resin, is pressed onto a base ply, also impregnated with resin, but the resin used for impregnating the outer ply is not an epoxide resin, as is mostly used for the base ply of ski compo-nents, but a different resin, for example a phenolformaldehyde resin. This has the advantage that such ski components, which evidently are not intended as the outer plies of a ski, do not -produce a dust detrimental to health when grinding the surface to permit it to be glued satisfactorily to further plies.

33~3~

1 All these processes are labor-intensi~e, require two ~;
or more impregnation processes and, for economic reasons, require sizable production runs.
By using the present invention it is possible to pro-duce, in an economical process, decorati~e, fiber-reinforced components which are in particular suitable for use as a ski surface. ~ -Throughout the present application, the base ply~ when in aprecured ~orm, is a prepreg comprising a fibrous material impregnated with a thermosetting synthetic resin, which resin is only partially cured. That is, the base ply in which theresin is in a precured state or 'B-state" and in which the resin is not completely cured may be referred to as the prepreg. When the prepreg is pressed under the influence of heat and pressure (by which pressing the thermosetting synthetic resin may be completely cured and hardened) a certain amount of resin is squeezed out from the fibrous material. The flow is a measure o~ the extent to which resin is s~ueezed out from the fibrous material. The flow is measured in a normalized test for any - ~ given base ply in a precured form ~i.e. pre-prepreg), in which the base ply is pressed under specific conditions of pressure and temperature for a fixed period of time and in which the weight of the base ply is determined after pressing so as to exclude the weight of resin previously existing in the prepreg which is squeezed out from the fibrous material. The flow is defined as the ratio of the difference between the weight of the base ply before pressing (i.e~, the weight of the prepreg) and the weight of the base ply after pressing to the weight of the base ply before pressing (i.e., the weight of the prepreg), expressed as a percentage and is determined, for the purposes of this application, under pressing conditions of 150C and

2 kpfcm2 for lO minutes, ~;

iL~83938 1 In addition to the above defined term "flow", the base ply is also described in this application by xeference to the weight of the thermosetting synthetic resin in the base ply, expressed as a percentage of the total weight of the base ply. :
The present invention relates to a process for the manufacture of laminates for ski components, especially those for ;
forming the upper or lower outer ply, which consist of a fiber-reinforced base ply of a thermosetting synthetic resin, which has been obtained by polymerization or polyaddition, and at least .
one outer ply based on absorbent material, the plies being joined : .
, ',' -2a-,.. ~. ~

~3938 .

1 to one another under pressure, and whilst curing the thermoset-ting synthetic resin, in which process at least one ply of the absorbent material iB pressed onto the base ply, which is in a precured form, and which contains 40 - 70% by weight of a thermo-setting synthetic resin, the flow of the said resin of the said `~
base ply being between 10% and 60%, measured under a pressure of 5 kp/cm2 at 150C, over a period of 10 minutes, and the ply or plies of the absorbent material are completely impregnated by the resin available from the base ply, and all plies are joinea to one another and fully cured.
Woven fabrics, fleeces or other fibrous products areimpregnated with a higher than customary amount of syr.thetic resin, namely to 40 - 70~ by weight of impregnated fibrous product, so that on pressing the combination, sufficient resin is available for the outer plies, to be placed on the base ply, to impregnate these outer plies and form a surface film thereon.
The amount of resin used depends on the "flow" requir-ed. This "flow'i must be at least 10% under pressing condi-tions of 5 kp/cm2 at 150C, with lO minutes duration, in order to achieve the effect of the invention. If the base ply is im-pregnated with the maximum amount of resin, namely 70~ by weight of the base ply, the Elow should not exceed 60% since depletion of resin in the base ply may otherwise result.
The choice, within the limits according to the inven-tion, of the ratio of resin component to reinforcing ibrous material in the prepreg which serves as the base ply is intended to ensure that under the conditions of pressing sufficient liquid resin is available to penetrate the outer plies completely and thus to ensure a perfect layer of resin on the surface. Of course it is in this context necessary to take into account how "~ .

~ ~ -3- ;

. . , ,. , -.: , ' ~," : ! ' ., :' , '' '~ .. '" .t/ , ,, ',' lQ8393~

1 thick the outer ply to be impregnated should be. As a rule, a thinner outer ply will require a lower resin concentration in the base ply than that which must be used if the outer ply is thicker. Of course, the fluidity of the resin of the base ply here also plays a part, so that even if there is sufficient resin available in the base ply it is necessary to ensure that the flow is sufficiently high to ensure perfect ~0 - ~:

~3a~
~J

. .. - . ~ . . , : , .

i~83938 1 impregnation of the outer ply, Hexe again~ the flow selected will have to increase ~ith increasing thickness o~ the outer ply so that, for example, a flow corresponding to the bottom limit of 1~% is fully adequate for an outer ply of 7Q - 8Q g/m , whilst for a thicker outer plyf for example of over lOQ~ or even 150 g/m2, it is advisa~le to use a higher flow~ Pressing is carried :
out under the conventional conditions for the manufacture o~
~uch laminates For example, it i5 pos~i~.le to use a pressure of about 5 - 15 kptcm2 at l~Q.- 160C~ :
By using decorative we~s of paper, fleeces or similar materials, or using colored-resins and non-colored we~s for the outer ply, any desired surface effects can be achieved The use -:
of absorbent materials, of resins which have good flow and~or o suitable pressing conditions is a preconditlon for perfect success of the process The base pl~consistS predominantly of preimpregnated ;
glass fi~ers but these can also he replaced entirely or partially ::
by carbon fi~ers, and these fi~ers can preferably be in the form of woven fabrics or other sheet-like products obtained from ~.
textile glass and/or from other reinforcing fibers such as, for example, carbon Eibers~ It is particularly advantageous to use, for example~ woven fabrics from spun glass fi~ers, ~ùt other mixtures of heavily felted fleeces can also be used~ Outer plies to be mentioned are a~ove all paper, absor~ent fleeces made from cellulose, cotton or glass, and also mixed fleeces.
Thermosetting resins, obtained ~y polyaddition or poly~
merizationr which should ~e mentioned are, a~o.e all, ~33938 .. . . ~
1 epoxide resins and unsaturated polyester resins, especially those which are modified with diallyl phthalate.
The advantage of the process according to the inven-tion is that only one impregnating process is required, that the end product is homogeneous in respect of the plastic and that the surface is 50 smooth and perfect that grinding it, in order to glue a covering film onto it, is superfluous.
The examples which follow are intended to explain the process in greater detail.
I0 Example 1:
The base ply with a resin content of 50% by weight is produced by impregnating a unidirectional glass fiber fabric, weighing 500 g/m2, with 500 g/m2 of an epoxide resin of the bis-phenol A diglycidyl ether type containing an amine curing agent, the resin being formulated to give a flow of 10%. The base ply (prepreg) is then pressed together with an absorbent colored ~-celLulose paper, weighing 80 g/m2, at about 150C and 5kp/cm2.
The laminate taken out of the press after it has coaled down -again consists of an about 0.4 mm thick ply of glass fiber-re-inforced plastic (GRP ply) and an about 0.1 mm thick outer ply.
Example 2: ;
The base ply consisting of 2 layers of glass fiber fabric as in Example 1, impregnaked to a resin content oE about 45% by weight, in which the resin is formulated to a flow of 20%, is pressed together with a layer of absorbent paper, weighing 160 g/m2, at 130C and 12 kp/cm2 for 30 minutes. A
laminate comprising an about 0.8 mm thick ply of a glass fiber-reinforced plastic and an 0.15 mm thick outer ply is produced.

3~

_ 5 ,.. i ~

1~8393~

t Example 3 The base ply consisting of a layer of glass fiber fabric as in Example 1, impregnated to a resin content of about : -55% by weight of an epoxide resin iormulated to a flow of 15%, is pressed together with layers applied to either side, of a decorative paper, weighing 80 g/m2, at 5 kp/cm2 and about 150C.
A laminate comprising an 0.4 mm thick ply of a glass fiber-reinforced plastic and two about 0.1 mm thick outer plies, on .
either side, is produced.
Example 4: 2 Unidirectional glass fiber fabrics weighing 500 g/m , impregnated with an epoxide resin mixture like that descri~ed ~.
in Example 1, but colored and formulated to a flow of 15%, are covered respectively with a cellulose fleece, a cotton fleece, a cellulose/cotton mixed fleece or a glass fleece, each of these fleeces weighlng 100 g/m2. The combinations are pressed under a pressure of 5 kp/cm at about 150C. Laminates are produced, which in each case comprise an about 0.4 mm thick base ply of ::.
glass fiber-reinforced plastic and an about 0.2 mm thick outer ply colored in accordance with the color of the epoxide resin, Example 5:. .
The procedure ~ollowed is as in Example 4, but the :`~
~iber reinforcement used for the base ply is a glass fiber fabric wherein the warp threads are entirely or partially ~.
replaced by carbon fiber threads, The outer ply is a rayon fleece weighing 100 g/m~. The tensile E-modulus and.the tensile strength are increased compared to the analogous laminate obtained in accordance with Example 4.

-:108393~
. .. - ;

, 1 ~xample 6:
The procedure followed is as in Example 1, but the synthetic resin used is an unsaturated polyester, with diallyl phthalate as a crosslinking agent and di-t-butyl peroxide as a curing agent. The flow of the prepreg during impregnation ~ ~
is for.~ulated to 15%, which ensures complete impregna-tion of . `
7 the outer ply. The press pressure is 7 k~/om2 at lL~5C.

'":

''~' . . .

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for the manufacture of laminates for ski components, especially those for forming the upper or lower outer ply, which consist of a fiber-reinforced base ply of a thermosetting synthetic resin, which has been obtained by poly-merization or polyaddition, and at least one outer ply based on absorbent material, the plies being joined to one another under pressure, and whilst curing the thermosetting synthetic resin, in which process at least one ply of the absorbent material is pressed onto the base ply, with is in a precured form, and which contains 40 - 70% by weight of a thermosetting synthetic resin, the flow of the said resin of the said base ply being between 10%
and 60% measured under a pressure of 5 kp/cm2 at 150°C, over a period of 10 minutes, and the ply or plies of the absorbent material are completely impregnated by the resin available from the base ply, and all plies are joined to one another and fully cured.

2. A process according to claim 1, characterized in that the ply or plies of absorbent material weigh 70 - 80 g/m2 and the flow of the base ply is 10 - 15%.

3. A process according to claim 1, characterized in that the ply or plies of absorbent material weigh 100 - 150 g/m2 and the flow of the base ply is 15 - 30%.

4. A process according to claim 1, characterized in that the fiber reinforcement of the base ply is a glass fiber fabric.

5. A process according to claim 1, characterized in that the fiber reinforcement of the base ply is a mixed fabric of glass fibers and carbon fibers.

6. A process according to claim 1, characterized in that the thermosetting synthetic resin is an epoxide resin.

7. A process according to claim 1, characterized in that paper is used as the ply of absorbent material.

8. A process according to claim 1, characterized in that a fiber fleece, whereof the fibers are cellulose fibers or cotton fibers, is used as the layer of absorbent material.

9. A process according to claim 1, characterized in that a blass fiber fleece is used as the layer of absorbent material.