CA1221216A - Production of sheet-like moldings of fiber-reinforced nylon - Google Patents
Production of sheet-like moldings of fiber-reinforced nylonInfo
- Publication number
- CA1221216A CA1221216A CA000458663A CA458663A CA1221216A CA 1221216 A CA1221216 A CA 1221216A CA 000458663 A CA000458663 A CA 000458663A CA 458663 A CA458663 A CA 458663A CA 1221216 A CA1221216 A CA 1221216A
- Authority
- CA
- Canada
- Prior art keywords
- mold
- nylon
- lactam
- sheet
- production
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
- C08J5/0405—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres
- C08J5/043—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres with glass fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/40—Shaping or impregnating by compression not applied
- B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
- B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
- B29C70/48—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM], e.g. by vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
- B29K2105/0854—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns in the form of a non-woven mat
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2709/00—Use of inorganic materials not provided for in groups B29K2703/00 - B29K2707/00, for preformed parts, e.g. for inserts
- B29K2709/08—Glass
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
- B29L2031/3055—Cars
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
- B29L2031/3076—Aircrafts
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
- C08J2377/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
Abstract
Abstract of the Disclosure: Sheet-like moldings of fiber-reinforced nylon are produced by activated alkaline polymerization of a lactam melt in a mold which contains a textile fiber structure, preferably a glass mat. In this process, the lactam melt is forced, in the course of from 2 to 50 sec, into a mold heated at from 120 to 180°C
and is polymerized in the course of less than 3 min to give a nylon having a K value greater than 100. The mold-ings can be used for the production of automotive and aircraft components.
and is polymerized in the course of less than 3 min to give a nylon having a K value greater than 100. The mold-ings can be used for the production of automotive and aircraft components.
Description
r;2 ~
~v - 1 - O.Z. 0050~366Z2 Product;on of sheet-like moldings of f;ber reinf ~
The present invent;on relates to a process for the production of sheet-like moldings from f;ber-re;n-forced nylons by alkaline polymerization of a lactam ina closed mold which contains reinforcing f;bers in the form of a textile fiber structure, eg. a glass fiber mat.
It is known that thermoplastics reinforced with glass mats can be produced by impregnating glass fiber mats continuously with a thermoplastic melt and compres-sing the product. In the case of nylons~ their high vis-cosity makes this process very difficult to carry out, and their high melting point furthermore means that it is very energy-consumptive.
Attempts have therefore been made to impregnate glass mats cont;nuously with a lactam and to subject th;s to alkaline polymer;zation. This process is carried out on a double-belt press under an inert gas atmosphere and therefore requires very expensive apparatus. Furthermore, only flat sheets can be produced by th;s procedure.
In the convent;onal alkaline lactam polymeriza-tion carried out by a batchwise procedure, the monomer ;s poured into an open mold and is polymerized therein.
Var;ous publ;cat;ons ~eg~ U.Sc Patents 3,451,975 and 3,341,501) ment;on that the polymer;zat;on can also be carr;ed out ;n the pressnce of additives, eg. glass fab-rics~ some of which are introduced into the mold even prior to polymerization. In order to achieve complete, -~ bubble-free impregnation of the glass mats with the Liquid monomer, relatively long cycle times are used, which means that a process carr;ed out on an ;ndustr;al scale will probably be uneconomical.
DE-A Z8 17 778 ind;cates that the lactam can also be injected ;nto a mold conta;n;ng glass f;bers. However, ;n the process described there, the lactam ;s introduced into a mold preheated to only 100C, and is heated to 175-220C in the mold itself, and polymerized. In this - Z - O.Z. 0050/366ZZ
case, too, the cycle times are long because the mold has to be heated to 175-~20C each time it has been charged w;th lactam and then has to be cooled to 100C again.
Moreover, we have found that, at polymerization tempera-tures above 170C, in part;cular above 180C, nylons hav;ng a low molecular weight and a relatively high resi-dual monomer content are formed, and the mechanical pro-perties are thus adversely affected~ Furthermore, there is a danger that the conventional activators will decom-pose at such high polymerization temperatures, producing bubbles at the surface of the mold.
It is an object of the present ;nvention to im-prove the conventional process for the production, by al-kaline lactam polymerization, of sheet-like moldings from nylon reinforced with textile fiber structures, the ;m-provement being such that moldings having good mechanical properties and a satisfactory surface are obtained in shor~ cycle times.
We have found that this object is achieved, in accordance with the invention, if the lactam melt is for-ced, in the course of from 2 to 50 sec, into a closed mold heated at from 120 to 1~0C, and is polymerized in the course of less than 3 min at from 120 to 180C to give a nylon having a K value greater than 100.
It is surprising that satisfactory impregnation of the textile sheet-like structure present in the mol~
takes place at all when liquid lactam is forced into the mold under superatmospheric pressure. On the basis of experience in polyurethane technology, it was to be ex-pected that the sheet-like textile structu~e would be swept away by the lactam melt forced in at high velocity, resulting in non-uniform impregnation and a large number of air bubbles.
The production of nylon moldings by activated al~
kaline lactam polymerization is known. It is described in detail in, for example, Kunststoff-Handbuch, Volume VI, Polyamide, Carl-Hanser-Verlag 1966, pages 46-49. In this - - 3 - O.Z. 0050/3662Z
procedure, the starting mater;als compr;se two components A and a, component A being a catalyst-conta;ning lactam melt, and component B be;ng an act;vator-conta;ning lac-tam melt. The two components are mixed~ transported ;nto a mold and polymer;zed there;n.
The preferred lactam ;s ~-caprolactam, but it is also poss;ble to use pyrrol;done~ caprylolactam, lauro-lactam, enanthlactam and the corresponding C-subst;tuted lactams. The lactams may also be modified, for example with polyetherols or isocyanate prepolymers, or with bis-acyl lactams as described in U~S. Patent 4,031,164.
The polymerization of the lactam ;s carried out in the presence of from 10 to 75, preferably from 1û to 60, X by weight, based on the ready~prepared molding, of a textile f;ber structure which is introduced into the mold prior to polymerization. The fiber structure can be in the form of a mat, a non-woven, a ~oven fabr;c or felt.
The fibers can consist of glass, carbon, aromatic nylon or a natural mater;al, such as cotton.
2û 6lass mats having a weight per unit area of from 150 to 1200 g.m Z are preferred. The mats can be compac-ted mechanically in a conventional manner by means of needles, or can be bonded by means of conventional binders, eg. polyurethanes. The diameter of the fibers is prefe-rably from 7 to 20 ~m, and the glass fibers are advanta-geously sized with a conventional size which does not interfere with the polymerization, as described in, for example, US-A 4 358 502.
~; Examples of suitable catalysts are alkali metal 3û compounds and alkaline earth metal compoun~s of lactams, such as sodium -caprolactamate, or of short~chain ali-phat;c carboxylic acids, such as sodium formate or potas-sium formate, or of alcohols of 1 to 6 carbon atoms, such as sodium methylate or potassium tert.-butylate. It is also possible to use alkali metal or alkaline earth metal hydrides, hydroxides or carbonates, as ~ell as Grignard compounds. The catalysts are usually employed in amounts ~:~LZ3L~6 - 4 - O.Z. 0050/36622 of from 0.1 to 10 mole X based on the total amount of lac-tam.
Su;table act;vators are N-acyllactams, such as N-acetylcaprolactam, b;sacyllactams, substituted triazines, carbodiimides, ketenes, cyanam;des, mono- and polyiso-cyanates and masked isocyanate compounds. They are pre-ferably employed in amounts of from û.1 to 10 mole X.
The impact strength of the molding materials can be increased by means of conventional additives, such as polyalkylene glycol~ having molecular weights of from 2000 to 1ûO,OOO, or by adding reactive or non-reactive rubbers, eg. graft polymers.
The polymerization of the lactam can be carried out in the presence of a convent;onal stabilizern A com-bination of CuI and KI ;n a molar ratio of 1:3 is par-ticularly advantageous, this combination being added to the activator-containing component B in amounts corres-ponding to 50-100 ppm, based on the total amount of lac-tam, of copper. Other suitable stabilizers are crypto-phenols and aminesA
Other additives are inorganic f;llers which do notinterfere w;th the polymerizat;on, eg. metal powders, powdered quartz~ metal oxides, graph;te, carbon black, silica gel, pigments, wo~lastonite and chalk, which are used in amounts of froM 10 to 60X by weight, based on the molding. It ;s also poss;ble to add light stabilizers, optical brighteners, flameproofing agents, crystallization accelerators, eg. talc or nylon-Z,2, lubricants, such as molybdenum sulfide, and shrinkage-reduc;ng substances.
It has proven particularly advantageous to add antifoams in amounts of from O.û5 to 5, preferably from 0.1 to 1, X by weight, such substances preventing the in-clusion of air bubbles in the molding. Preferred ant;~
foams are 5-ZOX strength by weight solutions of d;ene polymers, in particular polybutadier,e, in organic solvents, in particular aromatic solvents. Antifoams of this type are supplied by Mallinckrodt and have the names R~YK A 50û
az~6 ~ 5 ~ O.Z.'OOSOt36622 and A 501~
It is also advantageous to add internal release agents in amounts of from 0.05 to 2X by weight, eg. cal-cium, sodium or potassium stearate, stearyl stearate or octadecyl alcohol.
The procedure used in the novel process corres~
ponds to a modified reaction injection molding (RIM) tech-nique described for polyurethanes, for example by Piechota and R~ohr' in "Integralschaumstoffe, Carl~Hanser-Verlag, 197S, pages 34 to 37.
The two components A and ~ are heated separately in kettles to a temperature above the melting point of the lactam, preferably 80-140C, and are transported by means of hydraulically driven, heated plunger pumps through heated pipes to a mixing head which is Likewise heated.
When the material is pressed into the mold, the plunger of the m;xing head is drawn back, and the two accurately ., metered components enter the open mixing chamber, are mixed intimately therein and are pressed into the mold which is connected by means of a flange. This takes place in general under a pressure of more than 1, preferably from 1.1 to 300, in particular from 2 to 30, bar. How-ever, it is also possibLe in principle to carry out the procedure under atmospheric pressure if, by using special apparatuses, care is taken to ensure that the melt is sprayed sufficiently rapidly into the mold. Transfer of the lactam melt from the mixing head into the mold is complete in the sourse of from 2 to 50, preferably from 3 to 20~sec. The mold need not be flushed with nitrogen.
In accordance with the invention, the mold is pre-heated to 120-180C, preferably 125-160C, in particular 130-150C. Since the textile fiber structure has been introduced into the mold beforehand, it also assumes the mold temperature. The lactam melt warms up rapidly in the mold to reach the temperature of the latter, and poly-merizes in the course of less than 3 min. In general~
the ready-prepared molding can be removed from the mold :~
~L2~ 216 - 6 ~- O~Z. 0050/36622 after as little as 1 to 2 minutes. At a polymerization temperature of from 1Z0 to 180C, the resulting h;gh molecular weight nylon has a K value (according to Fikent-scher, Cellulosechemie 13, page 58) greater than 100, preferably from 110 to 160, and contains less than 3X, preferably less than 2%, of monomers and oligomers. The K value can be controlled by adding convent;onal regula-tors, for example long-cha;n al;phat;c monoamines, such as stearylamine, or crossl;nking agents, such as methyl-eneb;scaprolactam.
The process accord;ng to the ;nvent;on can be used to produce large sheet-l;ke mold;ngs, for example panels hav;ng a thickness of from 0.5 to 20 mm. These, be;ng sheet-l;ke preshapes, can be processed further to g;ve finished components by pressing at above the melting point of the nylon. Ho~ever, if appropriately shaped molds and contoured mats are used, it is also possible to produce finished components directly.
The moldings produced using the novel process possess good mechaniçal properties and a satisfactory sur-faceO They are particularly useful as shaped articles for the automotive and aircraft industries, for example for bodywork co~ponents, such as fenders and doors, for ;ndustr;al housings and for the product;on of sandwich components.
In the Example which follows~ percentages are by ~eight.
EXAMPLE
Formulation for Com onent A:
P
30 43.75 9 of caprolactam~
6.0 9 of a 17.5% strength solution of sodium lactamate in caprolactam and O.Z5 9 of a 14X solut;on of a modified polybutadiene in a m;xture of aromat;c hydrocarbons (R8YK A 500 ~- 35 from Mall;nckrodt).
Formulation for Comoonent B:
41.2S g of caprolactam, 12~ 16 - 7 - . O~Z. 0050/36622 8.5 9 o~ a solution of 83.5% of caprolactam and 16.5%
of hexamethylene di;socyanate and O.Z5 9 of BYK A 500.
Component A was preheated to 100C, while com-S ponent B was preheated to 128C. The components were m;xed, ;n a rat;o of 1:1, in a self-purging mixing head w;th a plunger produced by Elastogran Masch;nenbau, Strass-lach.
The mold cav;ty ~as a steel mold of ;nternal d;men-s;ons 640 x 240 x 4 mm, ;n wh;ch three glass mats having a we;ght per un;t area of 600 g.m 2 were placed one on top of the other without being f;xed. The mold together w;th the glass mats was preheated to 150C. The m;xture was transferred from the mix;ng head ;nto the mold under atmospher;c pressure ;n the course of 7 sec. Xt warmed up rap;dly to 150C, and polymer;zed to give 3 nylon ha-ving a K ~alue of 130. After 1.5 m;n~ ~he mold was opened and the completed molding was removed. It contained 35X
of glass fibers and had a smooth, bubble-free surface.
For comparison, a mold;ng was produced us;ng the sa0e apparatus and the method descr;bed in DE-A 28 17 778, the mold being preheated to only 100C, and subsequen~ly be;ng heated to 177C in the course of 15 min. After
~v - 1 - O.Z. 0050~366Z2 Product;on of sheet-like moldings of f;ber reinf ~
The present invent;on relates to a process for the production of sheet-like moldings from f;ber-re;n-forced nylons by alkaline polymerization of a lactam ina closed mold which contains reinforcing f;bers in the form of a textile fiber structure, eg. a glass fiber mat.
It is known that thermoplastics reinforced with glass mats can be produced by impregnating glass fiber mats continuously with a thermoplastic melt and compres-sing the product. In the case of nylons~ their high vis-cosity makes this process very difficult to carry out, and their high melting point furthermore means that it is very energy-consumptive.
Attempts have therefore been made to impregnate glass mats cont;nuously with a lactam and to subject th;s to alkaline polymer;zation. This process is carried out on a double-belt press under an inert gas atmosphere and therefore requires very expensive apparatus. Furthermore, only flat sheets can be produced by th;s procedure.
In the convent;onal alkaline lactam polymeriza-tion carried out by a batchwise procedure, the monomer ;s poured into an open mold and is polymerized therein.
Var;ous publ;cat;ons ~eg~ U.Sc Patents 3,451,975 and 3,341,501) ment;on that the polymer;zat;on can also be carr;ed out ;n the pressnce of additives, eg. glass fab-rics~ some of which are introduced into the mold even prior to polymerization. In order to achieve complete, -~ bubble-free impregnation of the glass mats with the Liquid monomer, relatively long cycle times are used, which means that a process carr;ed out on an ;ndustr;al scale will probably be uneconomical.
DE-A Z8 17 778 ind;cates that the lactam can also be injected ;nto a mold conta;n;ng glass f;bers. However, ;n the process described there, the lactam ;s introduced into a mold preheated to only 100C, and is heated to 175-220C in the mold itself, and polymerized. In this - Z - O.Z. 0050/366ZZ
case, too, the cycle times are long because the mold has to be heated to 175-~20C each time it has been charged w;th lactam and then has to be cooled to 100C again.
Moreover, we have found that, at polymerization tempera-tures above 170C, in part;cular above 180C, nylons hav;ng a low molecular weight and a relatively high resi-dual monomer content are formed, and the mechanical pro-perties are thus adversely affected~ Furthermore, there is a danger that the conventional activators will decom-pose at such high polymerization temperatures, producing bubbles at the surface of the mold.
It is an object of the present ;nvention to im-prove the conventional process for the production, by al-kaline lactam polymerization, of sheet-like moldings from nylon reinforced with textile fiber structures, the ;m-provement being such that moldings having good mechanical properties and a satisfactory surface are obtained in shor~ cycle times.
We have found that this object is achieved, in accordance with the invention, if the lactam melt is for-ced, in the course of from 2 to 50 sec, into a closed mold heated at from 120 to 1~0C, and is polymerized in the course of less than 3 min at from 120 to 180C to give a nylon having a K value greater than 100.
It is surprising that satisfactory impregnation of the textile sheet-like structure present in the mol~
takes place at all when liquid lactam is forced into the mold under superatmospheric pressure. On the basis of experience in polyurethane technology, it was to be ex-pected that the sheet-like textile structu~e would be swept away by the lactam melt forced in at high velocity, resulting in non-uniform impregnation and a large number of air bubbles.
The production of nylon moldings by activated al~
kaline lactam polymerization is known. It is described in detail in, for example, Kunststoff-Handbuch, Volume VI, Polyamide, Carl-Hanser-Verlag 1966, pages 46-49. In this - - 3 - O.Z. 0050/3662Z
procedure, the starting mater;als compr;se two components A and a, component A being a catalyst-conta;ning lactam melt, and component B be;ng an act;vator-conta;ning lac-tam melt. The two components are mixed~ transported ;nto a mold and polymer;zed there;n.
The preferred lactam ;s ~-caprolactam, but it is also poss;ble to use pyrrol;done~ caprylolactam, lauro-lactam, enanthlactam and the corresponding C-subst;tuted lactams. The lactams may also be modified, for example with polyetherols or isocyanate prepolymers, or with bis-acyl lactams as described in U~S. Patent 4,031,164.
The polymerization of the lactam ;s carried out in the presence of from 10 to 75, preferably from 1û to 60, X by weight, based on the ready~prepared molding, of a textile f;ber structure which is introduced into the mold prior to polymerization. The fiber structure can be in the form of a mat, a non-woven, a ~oven fabr;c or felt.
The fibers can consist of glass, carbon, aromatic nylon or a natural mater;al, such as cotton.
2û 6lass mats having a weight per unit area of from 150 to 1200 g.m Z are preferred. The mats can be compac-ted mechanically in a conventional manner by means of needles, or can be bonded by means of conventional binders, eg. polyurethanes. The diameter of the fibers is prefe-rably from 7 to 20 ~m, and the glass fibers are advanta-geously sized with a conventional size which does not interfere with the polymerization, as described in, for example, US-A 4 358 502.
~; Examples of suitable catalysts are alkali metal 3û compounds and alkaline earth metal compoun~s of lactams, such as sodium -caprolactamate, or of short~chain ali-phat;c carboxylic acids, such as sodium formate or potas-sium formate, or of alcohols of 1 to 6 carbon atoms, such as sodium methylate or potassium tert.-butylate. It is also possible to use alkali metal or alkaline earth metal hydrides, hydroxides or carbonates, as ~ell as Grignard compounds. The catalysts are usually employed in amounts ~:~LZ3L~6 - 4 - O.Z. 0050/36622 of from 0.1 to 10 mole X based on the total amount of lac-tam.
Su;table act;vators are N-acyllactams, such as N-acetylcaprolactam, b;sacyllactams, substituted triazines, carbodiimides, ketenes, cyanam;des, mono- and polyiso-cyanates and masked isocyanate compounds. They are pre-ferably employed in amounts of from û.1 to 10 mole X.
The impact strength of the molding materials can be increased by means of conventional additives, such as polyalkylene glycol~ having molecular weights of from 2000 to 1ûO,OOO, or by adding reactive or non-reactive rubbers, eg. graft polymers.
The polymerization of the lactam can be carried out in the presence of a convent;onal stabilizern A com-bination of CuI and KI ;n a molar ratio of 1:3 is par-ticularly advantageous, this combination being added to the activator-containing component B in amounts corres-ponding to 50-100 ppm, based on the total amount of lac-tam, of copper. Other suitable stabilizers are crypto-phenols and aminesA
Other additives are inorganic f;llers which do notinterfere w;th the polymerizat;on, eg. metal powders, powdered quartz~ metal oxides, graph;te, carbon black, silica gel, pigments, wo~lastonite and chalk, which are used in amounts of froM 10 to 60X by weight, based on the molding. It ;s also poss;ble to add light stabilizers, optical brighteners, flameproofing agents, crystallization accelerators, eg. talc or nylon-Z,2, lubricants, such as molybdenum sulfide, and shrinkage-reduc;ng substances.
It has proven particularly advantageous to add antifoams in amounts of from O.û5 to 5, preferably from 0.1 to 1, X by weight, such substances preventing the in-clusion of air bubbles in the molding. Preferred ant;~
foams are 5-ZOX strength by weight solutions of d;ene polymers, in particular polybutadier,e, in organic solvents, in particular aromatic solvents. Antifoams of this type are supplied by Mallinckrodt and have the names R~YK A 50û
az~6 ~ 5 ~ O.Z.'OOSOt36622 and A 501~
It is also advantageous to add internal release agents in amounts of from 0.05 to 2X by weight, eg. cal-cium, sodium or potassium stearate, stearyl stearate or octadecyl alcohol.
The procedure used in the novel process corres~
ponds to a modified reaction injection molding (RIM) tech-nique described for polyurethanes, for example by Piechota and R~ohr' in "Integralschaumstoffe, Carl~Hanser-Verlag, 197S, pages 34 to 37.
The two components A and ~ are heated separately in kettles to a temperature above the melting point of the lactam, preferably 80-140C, and are transported by means of hydraulically driven, heated plunger pumps through heated pipes to a mixing head which is Likewise heated.
When the material is pressed into the mold, the plunger of the m;xing head is drawn back, and the two accurately ., metered components enter the open mixing chamber, are mixed intimately therein and are pressed into the mold which is connected by means of a flange. This takes place in general under a pressure of more than 1, preferably from 1.1 to 300, in particular from 2 to 30, bar. How-ever, it is also possibLe in principle to carry out the procedure under atmospheric pressure if, by using special apparatuses, care is taken to ensure that the melt is sprayed sufficiently rapidly into the mold. Transfer of the lactam melt from the mixing head into the mold is complete in the sourse of from 2 to 50, preferably from 3 to 20~sec. The mold need not be flushed with nitrogen.
In accordance with the invention, the mold is pre-heated to 120-180C, preferably 125-160C, in particular 130-150C. Since the textile fiber structure has been introduced into the mold beforehand, it also assumes the mold temperature. The lactam melt warms up rapidly in the mold to reach the temperature of the latter, and poly-merizes in the course of less than 3 min. In general~
the ready-prepared molding can be removed from the mold :~
~L2~ 216 - 6 ~- O~Z. 0050/36622 after as little as 1 to 2 minutes. At a polymerization temperature of from 1Z0 to 180C, the resulting h;gh molecular weight nylon has a K value (according to Fikent-scher, Cellulosechemie 13, page 58) greater than 100, preferably from 110 to 160, and contains less than 3X, preferably less than 2%, of monomers and oligomers. The K value can be controlled by adding convent;onal regula-tors, for example long-cha;n al;phat;c monoamines, such as stearylamine, or crossl;nking agents, such as methyl-eneb;scaprolactam.
The process accord;ng to the ;nvent;on can be used to produce large sheet-l;ke mold;ngs, for example panels hav;ng a thickness of from 0.5 to 20 mm. These, be;ng sheet-l;ke preshapes, can be processed further to g;ve finished components by pressing at above the melting point of the nylon. Ho~ever, if appropriately shaped molds and contoured mats are used, it is also possible to produce finished components directly.
The moldings produced using the novel process possess good mechaniçal properties and a satisfactory sur-faceO They are particularly useful as shaped articles for the automotive and aircraft industries, for example for bodywork co~ponents, such as fenders and doors, for ;ndustr;al housings and for the product;on of sandwich components.
In the Example which follows~ percentages are by ~eight.
EXAMPLE
Formulation for Com onent A:
P
30 43.75 9 of caprolactam~
6.0 9 of a 17.5% strength solution of sodium lactamate in caprolactam and O.Z5 9 of a 14X solut;on of a modified polybutadiene in a m;xture of aromat;c hydrocarbons (R8YK A 500 ~- 35 from Mall;nckrodt).
Formulation for Comoonent B:
41.2S g of caprolactam, 12~ 16 - 7 - . O~Z. 0050/36622 8.5 9 o~ a solution of 83.5% of caprolactam and 16.5%
of hexamethylene di;socyanate and O.Z5 9 of BYK A 500.
Component A was preheated to 100C, while com-S ponent B was preheated to 128C. The components were m;xed, ;n a rat;o of 1:1, in a self-purging mixing head w;th a plunger produced by Elastogran Masch;nenbau, Strass-lach.
The mold cav;ty ~as a steel mold of ;nternal d;men-s;ons 640 x 240 x 4 mm, ;n wh;ch three glass mats having a we;ght per un;t area of 600 g.m 2 were placed one on top of the other without being f;xed. The mold together w;th the glass mats was preheated to 150C. The m;xture was transferred from the mix;ng head ;nto the mold under atmospher;c pressure ;n the course of 7 sec. Xt warmed up rap;dly to 150C, and polymer;zed to give 3 nylon ha-ving a K ~alue of 130. After 1.5 m;n~ ~he mold was opened and the completed molding was removed. It contained 35X
of glass fibers and had a smooth, bubble-free surface.
For comparison, a mold;ng was produced us;ng the sa0e apparatus and the method descr;bed in DE-A 28 17 778, the mold being preheated to only 100C, and subsequen~ly be;ng heated to 177C in the course of 15 min. After
2 hours, the mold;ng was removed. The nylon had a K
value of 94 and contained 4X of monomer, resulting in poorer ~echanical properties, in particular poorer ten-s;le strength. The molding had a very poor surface.
value of 94 and contained 4X of monomer, resulting in poorer ~echanical properties, in particular poorer ten-s;le strength. The molding had a very poor surface.
Claims (3)
1. A process for the production of a sheet-like mold-ing from a nylon and 10-75% by weight of reinforcing fibers in the form of a textile fiber structure, in which a lactam melt containing a catalyst and an activator is introduced into a mold which contains the fiber structure and is polymerized in the mold, wherein the lactam melt is forced, in the course of from 2 to 50 sec, into the closed mold heated at from 120 to 180°C, and is poly-merized in the course of less than 3 min at from 120 to 180°C to give a nylon having a K value greater than 100.
2. A process for the production of a sheet-like mold-ing from a fiber-reinforced nylon as claimed in claim 1, wherein from 0.05 to 5% by weight of a solution of a di-ene polymer in an organic solvent is added as an anti-foam during the lactam polymerization.
3. Use of a molding as claimed in claim 1 for the production of finished components by compression at above the softening point of the nylon.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3325554A DE3325554A1 (en) | 1983-07-15 | 1983-07-15 | METHOD FOR THE PRODUCTION OF FLAT-SHAPED MOLDED PARTS FROM FIBER-REINFORCED POLYAMIDE |
| DEP3325554.7 | 1983-07-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221216A true CA1221216A (en) | 1987-05-05 |
Family
ID=6204053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000458663A Expired CA1221216A (en) | 1983-07-15 | 1984-07-11 | Production of sheet-like moldings of fiber-reinforced nylon |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0134992B1 (en) |
| CA (1) | CA1221216A (en) |
| DE (2) | DE3325554A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5980796A (en) * | 1994-08-01 | 1999-11-09 | G. Schwartz Gmbh & Co. Kg | Process for producing molded parts by polymerization of lactams in molds |
| US9186852B2 (en) | 2013-11-22 | 2015-11-17 | Johns Manville | Fiber-containing prepregs and methods and systems of making |
| US10717245B2 (en) | 2018-04-03 | 2020-07-21 | Johns Manville | System for producing a fully impregnated thermoplastic prepreg |
| US10857744B2 (en) | 2018-04-03 | 2020-12-08 | Johns Manville | System for producing a fully impregnated thermoplastic prepreg |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1007446A3 (en) * | 1993-09-07 | 1995-07-04 | Dsm Nv | Preparation method for molecular composites |
| DE19527154C2 (en) * | 1995-07-25 | 2001-06-07 | Inventa Ag | Thermoplastic deformable composite materials |
| BR112014017569B1 (en) * | 2012-01-19 | 2021-04-20 | Basf Se | composition, processes to obtain a solid polymeric phase and to produce a molded part, and, molded part |
| US11548245B2 (en) | 2013-11-22 | 2023-01-10 | Johns Manville | Fiber-containing prepregs and methods and systems of making |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1720352B2 (en) * | 1968-03-02 | 1975-02-20 | Basf Ag, 6700 Ludwigshafen | Process for the production of moldings by the activated anionic polymerization of lactams |
| DE2064598A1 (en) * | 1970-12-30 | 1972-07-13 | Bayer | Process for the production of hollow polyamide bodies |
| US4297389A (en) * | 1971-12-23 | 1981-10-27 | General Electric Company | Antifoaming resin compositions |
| DE2817778A1 (en) * | 1977-05-09 | 1978-11-23 | Firestone Tire & Rubber Co | FIBERGLASS REINFORCED POLYAMIDE COMPOSITIONS |
-
1983
- 1983-07-15 DE DE3325554A patent/DE3325554A1/en not_active Withdrawn
-
1984
- 1984-07-10 DE DE8484108064T patent/DE3474311D1/en not_active Expired
- 1984-07-10 EP EP84108064A patent/EP0134992B1/en not_active Expired
- 1984-07-11 CA CA000458663A patent/CA1221216A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5980796A (en) * | 1994-08-01 | 1999-11-09 | G. Schwartz Gmbh & Co. Kg | Process for producing molded parts by polymerization of lactams in molds |
| US9186852B2 (en) | 2013-11-22 | 2015-11-17 | Johns Manville | Fiber-containing prepregs and methods and systems of making |
| US10717245B2 (en) | 2018-04-03 | 2020-07-21 | Johns Manville | System for producing a fully impregnated thermoplastic prepreg |
| US10857744B2 (en) | 2018-04-03 | 2020-12-08 | Johns Manville | System for producing a fully impregnated thermoplastic prepreg |
| US11458696B2 (en) | 2018-04-03 | 2022-10-04 | Johns Manville | System for producing a fully impregnated thermoplastic prepreg |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3325554A1 (en) | 1985-01-24 |
| EP0134992A1 (en) | 1985-03-27 |
| DE3474311D1 (en) | 1988-11-03 |
| EP0134992B1 (en) | 1988-09-28 |
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