HK1047071B

HK1047071B - Fiber reinforced epoxy resin product and method for the manufacture thereof

Info

Publication number: HK1047071B
Application number: HK02108774.3A
Authority: HK
Inventors: 梁东保; 梁東保
Original assignee: 瑾亨企业株式会社
Priority date: 1999-04-28
Filing date: 2000-04-28
Publication date: 2007-01-12
Also published as: JP2002542965A; WO2000066338A1; HK1047071A1; CN1353637A; AU4435600A; CN1264665C

Abstract

A fiber reinforced epoxy resin product and a method for manufacturing the epoxy resin product is provided. The fiber reinforced epoxy resin product comprises a hardened epoxy resin mixture which includes epoxy resin, silica and a fibrous material, wherein the fibrous material is a material selected from the group consisting of glass fiber, carbon fiber, aramid fiber and Kevlar fiber or a mixture of these fibers, and at least one layer of glass fiber roving cloth is arranged parallel to each other in the hardened epoxy resin mixture. The method for manufacturing a fiber reinforced epoxy resin product comprises the steps of providing a mold for the product, applying a release agent to inner surfaces of the mold, providing at least one layer of glass fiber roving cloth in the mold, casting an unhardened epoxy resin mixture in the mold, pressing the epoxy resin mixture in the mold, hardening the epoxy resin mixture in the mold under a temperature between about 20 DEG C and about 80 DEG C for more than 30 minutes, releasing the hardened epoxy resin mixture from the mold, and curing the hardened epoxy resin mixture under a temperature between about 20 DEG C and 35 DEG C for about 24 hours to form the product.

Description

Fiber reinforced epoxy resin product and method of making the same

Technical Field

The present invention relates to a fiber-reinforced epoxy resin product and a method for manufacturing the same, and more particularly, to a fiber-reinforced epoxy resin product comprising a hardened epoxy resin mixture containing an epoxy resin, silica and reinforcing materials such as glass fiber, carbon fiber, aramid fiber and kevlar fiber, and at least one layer of glass fiber roving cloth, and a method for manufacturing the same.

Background

Generally, various methods such as a steel plate bonding method, a prestressing method, and a cross-sectional growing method can be used for reinforcing and repairing a concrete member.

The bending strength of the bridge deck or the shearing strength of the bridge piers is enhanced by adopting a steel plate bonding method. When the magnitude of the prestress is less than the desired value, a prestressing method is used in the concrete casting. When the number of the reinforcing rods and the size of the cross section of the concrete member are insufficient, a cross section reinforcing method is adopted.

Recently, the steel plate adhesion method is the most widely used one among the above-mentioned methods. In this method, the steel plate is bonded to the concrete surface by a cement material such as epoxy resin, and the transfer of shear stress between the concrete surface and the steel plate and the sufficient adhesive strength can be ensured.

However, in this method, continuous maintenance is required to maintain the adhesive strength between the concrete surface and the steel plate. Also, when the concrete member is exposed to seawater, it is difficult to sufficiently reinforce or repair because of corrosion of the steel plate or problems associated with durability of the cement material. Also, the member load increases as the number of steel sheets increases, wherein the steel has a relatively high specific gravity. Further, the steel plate is generally bonded on the bottom surface of the member. Therefore, a large number of man-hours and workers are required, thereby increasing costs.

By using Fiber Reinforced Plastic (FRP) plates instead of steel plates, problems caused by corrosion are avoided. However, FRP plates have so low a strength that it only functions as a covering for concrete surfaces.

In order to solve these problems, several improved methods have been proposed, such as the method described in korean laid-open publication No.174,161, entitled "epoxy resin sheet for reinforcing concrete member and method for manufacturing the same", filed by the present applicant, or japanese laid-open publication No.4-67946, entitled "thermosetting resin composite sheet". The resin board proposed in these methods includes a metal wire as a reinforcing material. However, the metal wires are corroded after a period of use, the adhesive strength between the resin material and the metal wires is reduced, and cracks or delamination in the resin sheet are also propagated. In addition, the weather resistance and chemical resistance of the metal wire are insufficient, and in most cases, physical properties such as tensile strength or compressive strength are deteriorated due to the decrease in adhesive strength.

Summary of The Invention

It is therefore an object of the present invention to provide a fiber reinforced epoxy resin product having improved physical and chemical properties and better weatherability and chemical resistance by mixing the epoxy resin with short fibers and casting the mixture into a mold in which at least one layer of glass fiber roving fabric is arranged. It is a further object of the present invention to provide a method for manufacturing such a fiber-reinforced epoxy resin product.

The fiber reinforced epoxy resin panels of the present invention may be used in a variety of fields, such as, 1) reinforcing and repairing various concrete members, 2) protecting the surface of concrete members in the presence of seawater, sewage, freeze-thaw damage or other chemical action, 3) reinforcing of tunnel linings, 4) corner casting panels for container terminals, 5) vehicle slides, and the like.

According to a preferred embodiment of the present invention, there is provided a method of manufacturing a fiber-reinforced epoxy resin product, comprising the steps of: providing a mold for the product; applying a release agent to the inner surface of the mold; placing at least one layer of glass fiber roving fabric in a mold; casting an uncured epoxy resin mixture into a mold; compressing the epoxy resin mixture in a mold; curing the epoxy resin mixture in the mold at between about 20 ℃ and about 80 ℃ for more than 30 minutes; demolding the hardened epoxy resin mixture from the mold; the hardened epoxy resin mixture is then cured at between about 20 c and 35 c for about 24 hours to form a product.

According to another preferred embodiment of the present invention, there is provided a fiber reinforced epoxy resin product comprising a hardened epoxy resin mixture comprising epoxy resin, silica and a fiber material, wherein the fiber material is a material selected from the group consisting of glass fiber, carbon fiber, aramid fiber and kevlar fiber or a mixture thereof, and at least one layer of glass fiber roving cloth placed in the hardened epoxy resin mixture in a position parallel to each other.

Brief description of the invention

The above and other objects and features of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which:

FIGS. 1A-1F illustrate an exemplary method of making a fiber reinforced epoxy resin product of the present invention;

FIG. 2 shows a cross-sectional view of a fiber reinforced epoxy board made according to the method of the present invention;

FIG. 3 depicts a cross-sectional view of a fiber reinforced epoxy board of the present invention bonded to a concrete member surface for reinforcement;

FIG. 4A shows a plan view of one application of the fiber-reinforced epoxy resin product of the present invention, namely, a corner casting panel;

FIG. 4B is a side view of the corner casting plate of FIG. 4A;

FIG. 4C shows an installation view of the panel of the present invention;

FIGS. 5A-5C show a vehicle slider made in accordance with the method of the present invention;

FIG. 6 is a bottom view of the installed vehicle slide;

fig. 7 depicts a cross-sectional view taken along line I-I of fig. 6.

Description of the specific embodiments

Fig. 1A-1F illustrate an exemplary method of making a fiber reinforced epoxy product according to the present invention.

Step (a): providing a rectangular mold (10) of a predetermined size and removing dirt or other unwanted matter therefrom. The mold (10) can be of various sizes and shapes depending on the end product application. Preferably, the mold (10) is composed of a durable metal and is reusable after cleaning of the inner surface.

Step (b): a conventional type release agent is coated on the inner surface of the mold (10) in a uniform thickness, and the release agent (20) easily separates the final product from the mold.

Step (c): a first layer of a fibrous web (30A) having a predetermined mesh size is placed in a mold (10) over a release agent (20). Prior to this, the first layer of web (30A) is cut to the appropriate size for the mold and may be impregnated with epoxy resin for strength. Preferably, the epoxy resin used for impregnation has the following physical properties: a viscosity of 380mPas (380csp), a gel time of about 15 minutes, a compressive strength of 1000kg/cm or more²Bending strength of 500kg/cm or more²Shear strength of 800kg/cm or more²Adhesive strength of 130kg/cm or more²A tensile strain at break rate of 0.02 or more and an expansion coefficient of 1.0X 10^-5-2.0×10^-5cm/cm/deg.C, and heat distortion temperature of 50-70 deg.C.

Step (d): the epoxy resin is mixed with the reinforcing fibre material in a ratio of 9: 1 and the mixture is cast onto a first layer of a fibre web (30A) impregnated with epoxy resin (first casting step). The mixture includes an epoxy resin, a small amount of cement, silica and a cut reinforcing fiber material. The reinforcing fiber material is selected from glass fibers, carbon fibers, aramid fibers and Kevlar fibers or mixtures thereof.

Preferably, the epoxy resin in this step has the following properties: specific gravity of 1.15-1.20, hardness of M70-M80, viscosity of 19,000-24,000cps, absorptivity of less than or equal to 0.14%, shrinkage of less than or equal to 1.1%, and epoxy equivalent of 180-230. Preferred properties of the silica are as follows: purity greater than or equal to 95%, specific gravity of 2.25-2.65, Mohs hardness of 6.5-7.0 and pH value of 7-9.

A step (e): after the first casting step, a second web (30B) having the same size and shape as the first web (30A) is placed in a mold, and an epoxy resin mixture is cast thereon (second casting step). When the second casting step is complete, the third web (30C) is positioned in the mold in a direction parallel to the first and second webs (30A, 30B). The number of fiber web layers can vary depending on the use of the final epoxy product. When used to reinforce and repair concrete members, the final epoxy product preferably has multiple layers, and, for example, the number of layers and fibers may be determined based on the desired strength increase from structural analysis.

After the first and second casting steps are completed, vibration is applied to the mold (10) by a vibrator so that the fiber network is moved into the epoxy resin mixture as shown in fig. 1E.

After the vibration step was completed, the epoxy resin mixture was hardened at 60 ℃ for 30 minutes and then compressed with a 1000kg load. Next, the epoxy resin mixture was hardened at 80 ℃ for 3 hours.

Step (f): the hardened epoxy resin mixture is demolded from the mold (10) and cured at between 25 ℃ and 30 ℃ for a predetermined time to form a fiber reinforced epoxy resin product (1). The mould (10) can be reused after removing dirt thereon.

Fig. 2 shows a cross-sectional view of a fibre-reinforced epoxy board manufactured according to the method of the invention.

Fig. 3 is a cross-sectional view of a fiber reinforced epoxy board bonded to a surface of a concrete member for reinforcement.

First, the surface of the concrete member (80) is pretreated. The surface area to be reinforced and repaired is determined and the compressive strength of the concrete element is measured. The size of the reinforcing plate is determined according to the required strength. Damaged parts of the concrete element are removed and the surface is pretreated. If necessary, the corroded steel reinforcing strip is repaired.

Next, the fiber reinforced epoxy resin plate (1) is fixed to the surface of the concrete member (80) by anchor bolts or chemical anchor bolts (84). The epoxy board (1) is spaced from the surface to be anchored by a gap of about 2 to about 6 mm. An adhesive epoxy is injected into the gap between the plate and the surface. It is preferred that the gap between the plate and the surface is as small as possible. The head of the anchor bolt (84) is removed or covered with an anchor bolt cover to prevent corrosion. Preferably the distance between the anchor bolts (84) to the edge of the panel is not more than 100mm and the length of the anchor bolts is at least 2-3 times the depth of the damaged part. About 9 anchor bolts are installed per square meter and typically the spacing between two anchor bolts is 30 cm.

Subsequently, an adhesive epoxy (90) is injected into the voids. Before injection, the periphery of the plate (1) is sealed with a sealant, preferably of the same type as the adhesive epoxy. Preferably, the bonding epoxy (90) has the same properties as the epoxy resin constituting the epoxy resin mixture but its viscosity is lower. The performance and operating conditions of the adhesive epoxy (90) are preferably checked using a model test. The adhesive epoxy resin (90) is injected under a certain pressure, such as 0.5-2.5kg/cm²Is injected into the void. The injection process is initially at a lower pressure and then slowly pressurized to avoid the formation of air bubbles. This step is carried out at 5-30 ℃.

After this injection step is completed, the adhesive epoxy is cured for 3 days, and the epoxy board is covered with a vinyl sheet or other material or the like to prevent rain or dirt. The head of the anchor bolt is removed for aesthetic purposes.

Fig. 4A shows a plan view of a corner casting panel as one application of the fiber reinforced epoxy resin product of the present invention. Fig. 4B shows a side view thereof, and fig. 4C shows the assembly of the panels.

The corner casting sheet (100) is an article of manufacture for protecting the container joint surfaces (110) from damage by container box corner components. The panels (100) are positioned to support the corners of the container.

These angle cast panels are made by the same steps as described above except that more layers of fiber web are included and the composition of some of the components are varied to increase strength. The plates can be made in various sizes, such as: {420 mm. times.1350 mm. times.20 mm }, {420 mm. times.600 mm. times.20 mm }, or {1000 mm. times.1350 mm. times.20 mm }.

Fig. 5A-5C illustrate a vehicle slider made according to the method of the present invention.

These vehicle sliders (200, 200A, 200B) are manufactured in various sizes by the same method as described above. The vehicle slider (200, 200A, 200B) is provided with a through hole (212) for fixing the bolt (210). Preferably, the fixing bolt (210) is more than 2 times greater than the height of the vehicle slider (200, 200A, 200B). The number of through holes (212) may vary depending on the length of the slider.

FIG. 6 is a bottom view of the assembled vehicle slide. Fig. 7 shows a cross-sectional view taken along the line I-I in fig. 6.

These vehicle sliders are manufactured in the same manner as described above, except that the epoxy resin mixture preferably has the following composition: 10-30 wt% of epoxy resin, 20-39 wt% of silica, 30-68 wt% of pebbles and 0.01-0.1 wt% of reinforcing substance, and more preferably 13.64 wt% of epoxy resin, 39.59 wt% of silica, 46.70 wt% of pebbles and 0.07 wt% of reinforcing fiber material.

Preferably, the web has the following properties: weight 550-610g/m²A density of 6.3 or more and a tensile strength of 1500kg/mm or more²And a flexural strength of 1295kg/mm or more²。

Furthermore, the epoxy resin mixture may contain inorganic materials having fire-resistant and self-extinguishing properties, such as aluminum hydroxide, antimony oxide, hydrogen bromide. In order to maintain the strength of the member, it is preferable that the epoxy resin mixture contains not more than 5% by weight of the inorganic material relative to the total weight of the epoxy resin mixture.

As shown in the drawing, the vehicle sliders (200, 200C) are arranged at predetermined intervals. The interval depends on the width of the vehicle, and vehicle sliders (200B) having inclined surfaces are arranged at both ends of a vehicle slider line.

After cleaning the position surface (300) of the slide block to be fixed, the vehicle is screwed (210)The slider (200) is fixed in this position. Next, the periphery of each slider is sealed with a sealant to form a resin gate and an air outlet. An adhesive epoxy (220) is injected into the interface between the surface and the slider to prevent water penetration and to ensure that the slider is firmly secured to the surface. Preferably, the thickness of the bonding epoxy layer is about 2mm to 6 mm. The injection step starts at a lower injection pressure and then gradually and slowly increases to a higher pressure in order to prevent the generation of air bubbles. Preferably, the injection pressure is 0.5-2.5kg/cm². The bonding epoxy performs the same as the bonding epoxy described above, except that the bonding epoxy has a lower viscosity and a setting time of about 3 hours.

After the injection step is completed, the adhesive epoxy is cured for more than 3 hours. An epoxy based paint may be applied to the surface of the vehicle slider. The above steps can also be used in the manufacture of angle cast panels.

Examples

An embodiment of manufacturing the concrete reinforcing plate and the vehicle slider is described below.

Example 1

A mold having a size of 1000mm × 1000mm × 11mm is prepared, a release agent is applied to the inner surface of the mold, and at least three layers of the fiber web are placed in the mold. Subsequently, an epoxy resin mixture comprising 30.1% epoxy resin, 0.5% cement by weight, 69.3% silica by weight and 0.1% short fibers by weight was cast into a mold and then the mold was vibrated. After curing at 60 ℃ for 30 minutes, the epoxy resin mixture was compressed with a 1000kg load. The epoxy resin mixture was further hardened at 80 ℃ for 3 hours and demolded from the mold. The hardened epoxy resin mixture was cured at 25-30 ℃ and humidity of 40-50% for 3 days. The properties of the final epoxy board were tested and the following results were obtained:

TABLE 1

Mechanical properties			Test results	Remarks for note
Mechanical properties			Test results	Remarks for note	Compressive Strength (kg/cm)²)		800	Strain at break rate 0.017
Direct tensile Strength (kg/cm)²)			340	Strain at break rate 0.017	Compressive Strength (kg/cm)²)		800	Strain at break rate 0.017
Direct tensile Strength (kg/cm)²)			340	Strain at break rate 0.017	Flexural Strength (kg/cm)²)		400
Modulus of elasticity	Compression (kg/cm)²)		74.000		Flexural Strength (kg/cm)²)		400
	Compression (kg/cm)²)		74.000		Stretching (kg/cm)²)	34.000
	Poisson ratio		Compression	0.34	Stretching (kg/cm)²)	34.000
Stretching			Compression	0.34	0.22
Stretching			Strain rate at break		0.22	Compression	0.020	0.017-0.037
Stretching	0.010	0.010-0.014				Compression	0.020	0.017-0.037
Stretching	0.010	0.010-0.014			Coefficient of thermal expansion		6.5×10-6
Weather resistance	Curing in water		Is not substantially affected	3 months old	Coefficient of thermal expansion		6.5×10-6
	Curing in water		Is not substantially affected	3 months old	Is placed in the air	Is not substantially affected	3 months old
	Chemical resistance			Strong acid and alkali resistance	Is placed in the air	Is not substantially affected	3 months old

As shown in table 1, the fiber reinforced epoxy resin plate has higher compressive strength and tensile strength than concrete, and also has considerably higher flexural strength.

From the samples cured in water and the samples placed in low-temperature air, the properties of the epoxy resin product of the present invention are not affected by weather conditions such as humidity, time of placing in water, and the epoxy resin product also has strong acid and alkali resistance. Thus, the epoxy resin products have proven to be suitable for use in places with severe conditions such as sea water, sewage, vehicle exhaust, and the like.

Example 2

A mold having a size of 800mm by 1500mm by 11mm was manufactured, a release agent was applied to the inner surface of the mold, and at least three layers of the fiber web were placed in the mold. Subsequently, an epoxy resin mixture comprising 23.9% epoxy resin, 1.5% cement by weight, 74.5% silica by weight and 0.1% short fibers by weight was cast into a mold and then the mold was vibrated. After curing at 60 ℃ for 30 minutes, the epoxy resin mixture was compressed with a 1000kg load. The epoxy resin mixture was further hardened at 80 ℃ for 3 hours and demolded from the mold. The hardened epoxy resin mixture was cured at 25-30 ℃ and humidity of 40-50% for 3 days. The results obtained from testing the properties of the final epoxy boards are essentially the same as in table 1.

Example 3

A mold having a size of 170mm by 150mm by 1000mm is manufactured, a release agent such as 700-NC or PS-100 is coated on the inner surface of the mold, and a plurality of layers of the web are placed in the mold. Subsequently, an epoxy resin mixture comprising epoxy resin, silica, reinforcing fibers, pebbles and an inorganic material is cast into a mold and air bubbles are removed from the mold, the residual amount of air bubbles being less than 4%. The epoxy resin mixture was subjected to a pressure of 800-1000kg and cured for 1-3 hours, and then released from the mold. The hardened epoxy resin mixture is cured at 25-30 ℃ and a humidity of 40-50% for 24 hours. The results obtained from testing the performance of the final epoxy vehicle slider were as follows:

TABLE 2

Performance of		Test results	Concrete and its production method
Performance of		Test results	Concrete and its production method	Compressive Strength (kg/cm)²)		1128	300
Direct tensile Strength (kg/cm)²)		360	340	Compressive Strength (kg/cm)²)		1128	300
Direct tensile Strength (kg/cm)²)		360	340	Flexural Strength (kg/cm)²)		450	400
Weather resistance	Curing in water	Is not substantially affected	Have an influence on	Flexural Strength (kg/cm)²)		450	400
	Curing in water	Is not substantially affected	Have an influence on	Is placed in the air	Is not substantially affected	Have an influence on
	Chemical resistance		Strong acid and alkali resistance	Is placed in the air	Is not substantially affected	Have an influence on	Is poor

As shown in fig. 2, the fiber reinforced epoxy vehicle slider has higher compressive and tensile strengths than concrete and also has a considerably higher flexural strength. Moreover, the durability is better than that of concrete. From the samples cured in water and the samples exposed to low temperature air, the epoxy resin products of the present invention are substantially unaffected by climatic conditions such as temperature and humidity, and the time of exposure to water. The epoxy resin product also has strong acid and alkali resistance. Thus, the epoxy resin products have proven suitable for use in harsh conditions such as sea water, sewage and vehicle exhaust.

The invention has been shown and described with reference to the preferred embodiments. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

Claims

1. A method of manufacturing a fiber reinforced epoxy resin product comprising the steps of:

(a) providing a mold for the product;

(b) applying a release agent to the inner surface of the mold;

(c) providing a layer of glass fiber roving fabric in a mold;

(d) casting an uncured epoxy resin mixture onto the glass fiber roving fabric in the mold;

(e) vibrating the mold to remove air bubbles from the uncured epoxy resin mixture;

(f) hardening the epoxy resin mixture in the mold at 20-80 ℃ for more than 30 minutes;

(g) demolding the hardened epoxy resin mixture from the mold; and

(h) the cured epoxy resin mixture was cured between 20 ℃ and 35 ℃ for 24 hours.

2. The method of claim 1, wherein the epoxy resin mixture comprises epoxy resin, silica, and a reinforcing fiber material selected from the group consisting of glass fiber, carbon fiber, aramid fiber, kevlar fiber, and mixtures thereof.

3. The method of claim 2, wherein the epoxy resin mixture further comprises cement.

4. The method of claim 2, wherein the epoxy resin mixture further comprises an inorganic material having fire resistant and self-extinguishing properties.

5. The method of claim 4, wherein the inorganic material is selected from the group consisting of aluminum hydroxide, antimony oxide, and hydrogen bromide.

6. The method of claim 1, further comprising the step of impregnating at least one layer of glass fiber roving fabric with an epoxy resin.

7. The method of claim 1, wherein the fiber reinforced epoxy product is a fiber reinforced epoxy board and steps (c) and (d) are repeated to provide at least two layers of glass fiber roving fabric.

8. The method of claim 7, wherein the epoxy resin mixture comprises epoxy resin, silica, and a reinforcing fiber material selected from the group consisting of glass fiber, carbon fiber, aramid fiber, Kevlar fiber, and mixtures thereof.

9. The method of claim 7, further comprising the step of impregnating said at least two layers of glass fiber roving fabric with an epoxy resin.

10. The method of claim 1, wherein steps (c) and (d) are repeated to provide at least two layers of glass fiber roving fabric, the hardening step is performed at between 60 ℃ and 80 ℃ for 1 to 3 hours, and the curing step is performed at between 20 ℃ and 35 ℃ and at a humidity between 30% and 60% for 24 hours.

11. The method of claim 10, wherein the number of air bubbles in the uncured epoxy resin mixture is maintained below 4%.

12. The method of claim 10, wherein the epoxy resin mixture comprises epoxy resin, silica, pebbles, and a reinforcing fiber material selected from the group consisting of glass fibers, carbon fibers, aramid fibers, kevlar fibers, and mixtures thereof.

13. The method of claim 12, wherein the epoxy resin further comprises an inorganic material having fire resistant and self-extinguishing properties.

14. A fiber reinforced epoxy resin product produced according to the process of claim 1, comprising:

a hardened epoxy resin mixture comprising an epoxy resin, silica and a fibrous material selected from the group consisting of glass fibers, carbon fibers, aramid fibers, kevlar fibers, and mixtures thereof; and

at least one layer of glass fiber roving fabric, which are placed parallel to each other in the hardened epoxy resin mixture.

15. The fiber reinforced epoxy resin product of claim 14, which is a panel comprising at least three layers of glass fiber roving fabric placed parallel to each other in the hardened epoxy resin mixture.

16. A vehicle slider member comprising a body made using the fiber reinforced epoxy product of claim 14, said body comprising a hardened epoxy resin mixture and a glass fiber roving fabric, said hardened epoxy resin mixture comprising epoxy resin, silica, and a fiber material selected from the group consisting of glass fiber, carbon fiber, aramid fiber, kevlar fiber, and mixtures thereof.

17. The vehicle slider component of claim 16, further comprising an adhesive epoxy layer to secure the component in a desired position.