DE2227738A1 - PROCESS FOR MANUFACTURING GLASS FIBER REINFORCED POLYESTER COMPOSITE PANELS - Google Patents

Description

DR. E. WIEGAND DIPL-ING. W. NIEMANN DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MUNICH HAMBURG

TELEPHONE: 55547 «8000 MD NCHEN 15,

TELEGRAMS: KARPATENT - NUSSBAUMSTRASSE IQ

June 7, 1972 W 41 172/72 - Κο / ΌΕ

Mitsubishi Gas Chemical Company, Inc. Tokyo / Japan

Process for the production of glass fiber reinforced polyester composite panels

The invention relates to a method for the production of composite panels, which are reinforced with a glass fiber Contain polyester resin coated substrate. In particular, the invention relates to a method for making composite panels one on one or both sides with a glass fiber reinforced Polyester resin coated substrate, with a layer of a sheet molding compound or a mass molding compound applied to one or both sides of a substrate and the resulting assembly hot-pressed.

3 098 0 7/11 6 1

According to the invention, composite panels that have a substrate, for example as a core made of plywood or particle board, coated with a glass fiber reinforced polyester resin, in a simple manner by application a layer of an arch molding compound or a bulk molding compound on one or both sides of the substrate and hot pressing of the arrangement for curing the unsaturated polyester resin and for sealing Adhesion of the glass fiber reinforced polyester layer to the substrate is established.

Composite panels made from a substrate, for example a core of plywood or particle board, are covered with a glass fiber reinforced polyester resin and are hereinafter referred to as "GRP composite panels" for abbreviation Are referred to are of great value as panels that are properly used in manufacture of containers, as wall cladding, as a floor panel) !, for building materials and for other various purposes due to the high mechanical strength, thermal resistance and chemical resistance and other beneficial properties of the glass fiber reinforced cured polyester resins, hereinafter referred to as "GRP" abbreviated, can be used. The known processes for the production of GRP composite panels can can be roughly divided into the following two types; One comprises the steps (1) of applying a glass fiber on the substrate, (2) the impregnation of the obtained layer of glass fibers with a liquid unsaturated Polyester resin by pouring on a suitable amount of a liquid resin composition, which consists of a mixture of an unsaturated Polyester resin, a catalyst, a promoter, a filler, a pigment, an inner Mold release agents and other common additives

309807/1161

and (3) after venting using Roll curing of the unsaturated polyester resin to form a GRP composite panel. In this procedure it is necessary, if both sides of the substrate are to be coated with GRP, the substrate after coating flip the top with GRP and then repeat the same application process. This method is referred to as the "hand lay-on method", but requires numerous manipulations, has a low one Productivity and is for coating a substrate with a large area from the viewpoint of processability not suitable. In addition, this method shows various additional disadvantages, for example that the handling of the liquid polyester resin composition is troublesome because of its stickiness, the molded GRP composite panels do not always have a high surface smoothness and the molded composite panels a monomer odor due to the unreacted copolymerizable Release monomers because the curing of the unsaturated polyester resin at relatively low temperatures due to the nature of the procedure must be carried out. When these drawbacks are taken into account, the result is it turns out that the laying on of hands method as a method for Production of GRP composite panels on an industrial scale is not advantageous.

Another method is the so-called "sticking method", that the steps of the separate production of a flat GRP sheet and Aufheftung'des GRP sheet on the substrate using a polyester or epoxy adhesive. This procedure is also for the technical production of GRP composite panels is not advantageous, since in this process the use of a separate expensive adhesive is required because the

3 0 9 8 0 7/1161

Polyester resin in the GRP not as an adhesive for bonding of the GRP is applied with the substrate and it further comprises multiple stages. In addition, the layer located between the GRP and the substrate the adhesive occasionally has an adverse effect on, for example, the mechanical strength of the composite panel.

In both the hand lay-on process and the glue-on process, it is usually necessary to to achieve an improved surface smoothness for the GRP composite panels, apply a gel coating, and this inevitably brings about the disadvantage of increasing the number of stages.

An object of the invention is a method for producing GRP composite panels that are free are of such disadvantages as occur with the previous methods.

Another object of the invention is to provide a simplified, economical method of manufacture of GRP composite panels.

Another object of the invention is a method of making GRP composite panels with a excellent appearance and improved mechanical strength without any additional processing steps, for example a gel coating treatment step.

The method according to the invention consists in that

a molded joint in sheet or bulk form on one or both sides of a substrate of a plywood core or particulate cardboard is applied and the assembly thus formed is hot-pressed into a composite panel will.

3 0 9 8 0 7/1161

The molding compound, as it is in arc or
Bulk form used in the practice of the invention is well known and is widely used as a material for making glass fiber reinforced polyester moldings in compression molding processes
used. In practicing the invention
all commercially available arch forming compounds or mass forming compounds can be used,
although those having the following compositions are generally used.

A particularly suitable compound for the arch forming connection is the following:

Unsaturated polyester resin 35 to 45% by weight

Glass fibers "20 to 35% by weight

Catalyst 0.4 to 0.7 wt.

internal mold release agent 0.7 to 1.3 wt.

Filler 15 to 45 wt .- ^

Thickener 0.4 to 0.7 wt.

other additives 1 to 2 wt .- ^

The bond is in the form of a thickened, non-tacky sheet or sheet.

A suitable mass for the mass molding process is the following:

Unsaturated polyester resin 25 to 30% by weight

Glass fibers 15 to 20 wt .- $ catalyst - 0.4 to 0.7 wt.

internal form release agent 1.5 to 2.0 wt.

Filler 40 to 60 wt .- #

Thickener 0.5 to 1.0 wt.

other additives 1 to 2 wt .- ^

309807/1 161

The compound is in the form of a thickened, non-sticky mass.

The unsaturated polyester resins used in the production of such compounds are not limited, and unsaturated polyester resins which, for example, have high thermal resistance, chemical resistance and / or flame resistance are generally suitable for use. Those for specific or general purposes are also suitable for use. Maleic acid, maleic anhydride or fumaric acid are preferably used as the unsaturated dibasic acid of the unsaturated polyester. If desired, some of the unsaturated dibasic acid can be replaced, for example, by a saturated aliphatic or aromatic dibasic acid, for example adipic acid, phthalic anhydride or isophthalic acid. Ethylene glycol, diethylene glycol and 1,2-propylene glycol can be used as dihydric alcohols and some of the glycols can be replaced, for example, by 1,3-butanediol or 2,2-dimethyl-1,3-propanediol. Suitable copolymerizable monomers which can be used in the unsaturated polyester are vinyl monomers, such as, for example, styrene, vinyl toluene, chlorostyrene, acrylates, methacrylates. The term "unsaturated polyester resin" includes and describes mixtures of unsaturated polyesters which are copolymerizable by polycondensation between such a dibasic acid and a dihydric alcohol, as described above, with a copolymerizable monomer f) er ^e ixe $ ai ^< i ^e id'es Monomers in the unsaturated polyester resin according to the invention is generally in the range from 20 to 45% by weight and preferably between about 25 and 40% by weight.

309807/1 161

The glass fibers can be in the form of "for example chopped strands, chopped strand mats or woven cloths.

All known catalysts for unsaturated polyester resins, for example Benzoyl peroxide paste, tert-butyl perbenzoate and Dicumyl peroxide can be used in the usual manner.

As an inner Formfreigebungsmittel and I ¹ UlIstoff, can all such means as are conventionally used in synthetic resin molding compounds are used for example stearic acid, zinc stearate, and long chain alkyl phosphates such as those supplied by Du Pont Co. under the designation Zelex acts as inner lOrmfreigebungsmittel and calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, clay, silica, diatomaceous earth and ground glass can be used as the filler. As a thickening agent, it is generally possible to use all such compounds which show a chemical thickening effect on unsaturated polyester resins, for example magnesium oxide, calcium oxide, beryllium oxide, magnesium hydroxide and calcium hydroxide. Other additives include, for example, inorganic and organic pigments and like coloring agents for polyester resins.

The material of the plywood sheets used as the cores is not limited, and all products can be, for example Lauan, Apitong, Kapur and Douglas fir can be used. The number of layered layers of the core plywood can vary within certain limits. The moisture content of the core plywood is preferably 10% by weight or less from the point of view the adhesion of the GRP layer to the substrate. The core plywood used as the substrate includes a veneer core plywood with a core of one or more fur-

3 0 9 8 0 7/1161

kidney layers, a wood core plywood with a core made of wood, a cardboard core plywood with a core made of particle board, fiber board or paper board and a low density core plywood having a core of paper or aluminum honeycomb or one cellular synthetic resin. Although the core plywood as a substrate in the composite panels according to the invention is particularly suitable from the point of view of the mechanical strength of the product, a Particle board can be used in the same way

The arch forming compound can typically be of a thickness in the range 0.7 to 3 mm. The amount of mass molding compound is typically between about 1.0 kg to 3.5 kg per square meter.

The thickness of the GRP layer can be adjusted by adjusting the strength of the arch-forming compound used, the amount of arch forming connection or forming pressure can be varied.

Thus, in the method according to the invention, the arch molding compound or the mass molding compound is used placed on one or both sides of the substrate and then deformed, for example by hot pressing. Although the hot pressing is done by passing the assembly of substrate and arch forming compound through a roller press can be obtained, this method is not always due to hardenability and workability suitable in the GRP molding stage and a GRP-V. shaped in this way Vesicles on the surface. Therefore, the hot pressing is used in molding the GRP sheet according to the invention most conveniently using a hot press over the entire surface in a single pressing operation executed.

309807/1161

The molding conditions are selected according to the thickness of the GRP, for example in the production of composite panels with a GRP layer with a thickness of about 0.5 to 20 mm, the conditions being selected so that they are within the following ranges: molding temperature about 80 to 15O ⁰ C, molding pressure is about 3 to 50 kg / cm and molding time about 0.5 to 30'Minuten. A shaping

pressure within the range of about 5 to 20 kg / cm is preferable because excessive pressure breaks the substrate and a molding temperature door within the range of about 100 to 14O ⁰ C is preferred.

It can be seen from the above description that the method according to the invention is a new method for the production of GRP composite panels using an arch molding connection or a Majssen molding connection represents and according to the invention it becomes possible to produce GRP composite panels in high productivity in a very simple and economical process. Furthermore, according to the invention both sides of the substrate can be coated with GRP in a single pressing operation and a coating a substrate with a large surface area can be achieved without any difficulty. The procedure according to the invention is therefore very valuable as a method for the industrial production of GRP composite panels.

In addition, the GRP composite panels obtainable by the method according to the invention are excellent Surface smoothness so that the usual gel coating treatment is not necessary. Also will the GRP layer fully cured during the hot pressing and results in a GRP composite panel that does not have a Odor of unreacted copolymerizable monomers

3 0 9 8 0 7/1161

results. In the GRP composite panel formed in this way, the GRP layer is in good contact with the substrate and is firmly bonded so that no delamination can be detected during the peeling test. This result is shown when examining a cross section of the GRP composite board obtained by the method according to the invention, ie the hardened GRP resin composition has partially penetrated into the fibers of the wood, presumably as a result of hot pressing, and it is assumed that the anchoring effect of the hardened , in the fibers of the wood that has penetrated the resin, the strong bond between the GRP layer and the timber layer is obtained. Ea is likely to be due to the above effect of the invention obtainable according to the GRP composite panels commercially available, superior all in terms of bending strength and "screw attitude strength ¹¹ are. The GRP composite panels produced according to the invention can be used in a wide range, for example as panels for ship containers, dry cargo containers, cooling containers and similar various containers, structural components for motor vehicles and ships, building materials for use outside and inside the house3, sealing panels for thermal insulation materials or frame components of high quality for pouring concrete.

While according to the above description, the method according to the invention in terms of manufacture of flat GRP composite panels is that The method of the invention is not limited to this and also to the coating of uneven substrates GRP applicable using a suitable die.

The following examples serve to further illustrate the invention.

309807/1181

example 1

An arching joint with a width of 240 cm, a length of 610 cm and a thickness of 2 mm was used according to the usual method produced in the process according to the invention. The arch forming compound included the following Components:.

unsaturated polyester resin 36.0 parts

(obtained from propylene glycol, isophthalic acid and maleic anhydride with a content of 30 wt .- $ styrene, based on the total weight of the resin)

Fiberglass (chopped strand) 20.0 parts tert-butyl perbenzoate 0.4 parts Zinc stearate 1.1 parts ! DiO ₂ 2.2 parts CaCO ₅ 36.0 parts MgO 0.6 parts other accessories 3.7 parts

A five-layer phenolic-bonded xau anchor plywood 260 cm long, 630 cm wide and 12 mm thick was placed between two sheets of the arch-forming joint and then placed between two plates of a 2 mm thick mirror-faced stainless steel plate. The arrangement was hot-pressed at IAO ⁰ C under a pressure of 10 kg / cm for 5 minutes. Then the assembly was removed from the hot press and the steel plate removed therefrom, a GRP * composite panel having a thickness of 15 mm was obtained-

The GRP composite panel thus obtained had

3 0 9 8 0 7/1161

a very smooth and shiny surface and gave off no odor. When trying to peel off for determination the bond strength between GRP and the core plywood were all test pieces in the core plywood Broken. The peeling test was carried out by partially separating the GRP layer and substrate using a knife and peeling off the severed end of the GRP layer in a direction perpendicular to the surface of the substrate to observe the state of separation. A test piece of 50 mm 500 mm was made of the GRP composite panel and a flexural strength determination according to JIS K 6911 for a Clamping distance of 400 mm, a load of 16 mm / min., Beam with 2 edges, load on 2 lines, performed. The flexural strength determined in this way was 1457 kg / cm. The flexural strength of the Lauan

Plywood alone was about 620 kg / cm. From the GRP composite panel a test piece of 50 mm 300 mm was made and a through hole in one position 15 mm or 25 mm from each short side of the test piece educated. An 8 mm diameter screw was inserted into each of the through holes and the screws turned from each other in a direction parallel to the long side of the test piece to reduce the load, under which the test piece broke off, to be determined as "screw storage strength". The results are contained in the following table:

Distance between one
Edge of the test piece and the center
the through hole load to break

(mm) (kg)

15 _f 925

25 1350

309807/1161

Comparative example

The same unsaturated polyester resin, glass fiber, catalyst, fillers and other additives, as used to make the arch molding compound of Example 1 were used in the same Amount produced. They were used to form a GRP layer on the surface of the example 1 lukewarm plywood used according to the usual hand lay-up method, both surfaces of the plywood were coated with the GRP layer. The composite panel obtained in this way corresponded to a commercially available plate. Test pieces made from the GRP composite panel were used a determination of the flexural strength and the screw holding strength in the same way as in Example 1 subjected. The results are in the following Table listed.

Flexural strength 980 kg / cm

Screw holding strength

Distance between one

Edge of the trial piece

and the middle of a drilling

holes (mm) load to break (kg)

15th 700 • 25th 900 Example 2

An arched connection with a width of 100 cm, a length of 370 cm and a thickness of 2 mm was produced by a conventional method and at

309807/1161

method according to the invention used. The arch forming connection contained the following components;

unsaturated polyester resin 40 parts

(consisting of diethylene glycol, propylene glycol, isophthalic acid and maleic anhydride and with a content of 20 wt .- ^ styrene and 10 wt .- $ methyl methyl acrylate, each based on the total weight of the resin)

Glass fibers (chopped strands) 25 parts

tert-Biityl perbenzoate 0.5 parts

Zinc stearate. 1.3 parts

TiO ₂ 2.5 parts

CaCO ₃ 27.0 parts

MgO 1.0 part

further additions 2.7 parts

A seven-layer Apitong core plywood 120 cm wide, 400 cm long and 18 mm thick was placed between two sheets of the core molding joint and then between two sheets of a 2 mm thick mirror-faced stainless steel plate. The assembly was placed in a held at 135 ⁰ C hot press. The pressing pressure was immediately increased to 15 kg / cm and the assembly was hot-pressed under this pressure for 12 minutes. The assembly was then taken out of the hot press and the steel plate was removed therefrom, so that a 20 mm thick GRP composite panel was obtained. The product had a very smooth surface and gave off no odor. During the peeling test, 100% of the test pieces broke in the wood core. The flexural strength determined on a test piece of 50 mm 500 mm of the GRP composite board in the same manner as in Example 1 was 1250 kg / cm.

309807/1161

Example 3

A mass molding compound material for Application in the method according to the invention was after manufactured using the usual method and contained the following components:

unsaturated polyester resin 100 parts

(consisting of propylene glycol, isophthalic acid and maleic anhydride and with a content of 40 wt .- $ styrene, based on the total weight of the resin)

Glass fiber 60 parts

tert-butyl perbenzoate 2 parts

Zinc stearate 6 parts

CaCO ₅ 200 parts

MgO ''. 2.5 parts

other accessories 4i5 parts

A five-layer phenolic resin bonded Eapur core plywood measuring 100 cm 100 cm 12 mm was placed between two masses of the mass molding compound each weighing 2.3 kg and then placed between 2 mm thick mirror-faced stainless steel plates. The assembly was then placed in a held at 145 ⁰ C hot press. The pressure was immediately increased to 8 kg / cm and this pressure was maintained for 10 minutes. The assembly was then removed from the hot press and the steel plates removed from it, so that a GRP composite panel was obtained with a smooth, glossy surface that was odorless. During the peel test, the GRP composite panel always broke in the core plywood layer. For a test piece of 50 mm χ 500 mm from the GRP composite plate in the same way as in

309807/1161

Flexural strength determined in Example 1 was 1000 kg / cm.

Example 4

Following the procedure given in Example 1 was

an arch forming compound with an area of

2
12,000 cm and a thickness of 3 mm.

A 100 cm x 200 cm x 20 mm single layer particle board was sandwiched between two sheets of arch forming compound and then sandwiched between two sheets of a 2 mm thick mirror-faced stainless steel plate. The arrangement was made at

130 ⁰ C under a pressure of 15 kg / cm hot-pressed for 15 minutes. A GRP composite panel was obtained.

The value of the flexural strength of the composite panel was

2
a value of 650 kg / cm compared to a Pestig-

speed of about 280 kg / cm for the single-layer particle board alone increased.

The invention has been described above on the basis of preferred embodiments, but there are modifications and modifications are possible within the scope of the invention.

3 0 9 8 0 7/1161

Claims (10)

Claims ί 1y method of making composite panels of a substrate coated with a polyester resin reinforced by glass fibers, characterized in that daify by the application of a molding compound that an unsaturated polyester resin and glass fibers is obtained on at least one surface of the substrate Assembly is formed and this assembly is hot-pressed. 2. The method according to claim 1, characterized in that the substrate is a core plywood or a particle board is used. 3. The method according to claim 2, characterized in that the plywood consists of a veneer core plywood, a wood core plywood, a cardboard core plywood or a honeycomb plywood of low density or a low-density core plywood. 4. The method according to claim 1 to 3, characterized in that the hot pressing at a temperature of about 80 to 150 ⁰ C under a pressure of about 3 to 50 kg
will. 50 kg / cm for about 0.5 to 30 minutes 5. The method according to claim 1 to 4, characterized in that the hot pressing is carried out at a temperature of about 100 to 140 ⁰ C under a pressure of about 5 to 20 kg / cm for about 0.5 to 30 minutes. 6. The method according to claim 1 to 5 »characterized in that that the molding compound used in arch form and has a thickness of about 0.7 to 3 mm. 7- The method according to claim 1 to 5, characterized in that the Pormungsverbindungen used in bulk form and in an amount of about 1.0 to 3.5 kg 309807/1161 is used per square meter of substrate. 8. The method according to claim 1 to 5, characterized in that the molding compound is a sheet molding compound, 'the about 35 to 45 wt- $ unsaturated polyester resin, about 20 to 35 wt- $ fiberglass, about 0.4 to 0.7 wt. ^ of a catalyst, about 0.7 to 1.3% by weight of an internal mold release agent, about 15 to 45% by weight of a filler and about 0.4 to 0.7% by weight of a thickener is used. _t 9. The method according to claim 1 to 5, characterized in that the molding compound is a Msssenforimmgsverbindungen is used, which is about 25 to 30 wt. ~ - / £ an unsaturated polyester resin, about 15 to 20 wt.? Fiber glass, etv / a 0.4 to 0.7 wt .- ^ of a catalyst, about 1.5 to 2.0 wt .- ^ of an internal mold release agent, about 40 to 60 wt .- ^ of a filler and about 0.5 to 1.0% by weight of a thickener. 10. Composite panel, consisting of a substrate coated with glass fiber reinforced polyester resin, obtained by the method of claims 1 to p. 309807/1 161