KR20220095838A - Polyester film, glass fiber fabric compositie material comprising the same, and manufacturing method of the same - Google Patents

Abstract

An embodiment relates to a film for glass fiber fabric composite materials which comprises: a core layer, wherein the core layer includes a polyester resin, wherein the polyester resin has a melting point of 210 to 245℃ and a melt index at 250℃ of 20 to 80g/10min. The film can contribute to improving the workability and durability of the composite materials when processing the glass fiber fabric composite materials.

Description

Polyester film, glass fiber composite material containing same, and manufacturing method thereof

Embodiments relate to a polyester film, a glass fiber composite material comprising the same, and a method for manufacturing the same.

Recently, as a solution for improving fuel efficiency of transportation means including automobiles, research for weight reduction of automobiles and the like has been actively conducted. Glass fiber composite materials are attracting attention as a material to replace the materials of parts constituting existing automobiles. The glass fiber composite material has advantages in mechanical properties such as specific strength and specific modulus while being lighter in weight compared to existing metal materials.

Glass fiber composite materials include thermosetting composite materials and thermoplastic composite materials. A thermosetting composite material is a material in which a thermosetting resin layer is impregnated on a glass fiber fabric, and a thermoplastic composite material is a material in which a thermoplastic resin layer is impregnated on a glass fiber fabric.

The thermosetting composite material may have excellent mechanical properties and heat resistance. However, the thermosetting composite material cannot be recycled due to the nature of the applied resin, and the processing time is long, which increases the inefficiency of the process and may cause difficulties in mass production.

The thermoplastic composite material is recyclable due to the characteristics of the impregnated thermoplastic resin, the processing time is relatively short, and the processing after curing is easy, so that mass production is possible. However, if the physical properties of the resin applied to the thermoplastic composite material are not controlled, problems such as a decrease in productivity of the composite material production process, a decrease in workability, and a decrease in the mechanical properties of the composite material may occur.

The above-mentioned background art is technical information that the inventor possessed for the derivation of the embodiment or acquired in the process of derivation of the embodiment, and cannot necessarily be said to be a known technique disclosed to the general public prior to the filing of the present invention.

Domestic Patent Publication No. 10-2017-0128363 Domestic Registered Patent No. 10-1387031

An object of the embodiment is to provide a film for a glass fiber fabric composite material, which is easily impregnated and/or attached to a glass fiber fabric and is difficult to peel off.

Another object of the embodiment is to provide a film for a glass fiber composite material having a relatively low melting point, flowability is controlled during melting, so that it is easy to process at a low temperature and has stable heat resistance when manufacturing a composite material.

The film for a glass fiber fabric composite material according to an embodiment of the present specification includes a core layer.

The core layer includes one surface and the other surface positioned opposite to the one surface.

The core layer is disposed so that the one side is positioned on the glass fiber fabric, and after pressing at 260° C. and 1 MPa for 15 minutes, peel strength when peeled from the glass fiber fabric at a peel rate of 152 mm/min. More than 950 gf/inch.

The core layer may include a polyester resin.

The polyester resin may have a melting point of 210 to 245°C.

The polyester resin may have a melt index of 20 to 80 g/10min at 250°C.

The core layer may have a TD value of Equation 1 below 5%.

[Equation 1]

In Equation 1, T _max is the maximum thickness of the core layer, T _min is the minimum thickness of the core layer, and T _ave is the average thickness of the core layer.

The polyester resin may include an acid-modified polyester resin.

The acid-modified polyester resin may be a polyester resin grafted with an acid anhydride-based compound.

The polyester resin may include 0.1 to 0.5 parts by weight of a functional group derived from an acid anhydride-based compound based on 100 parts by weight of the polyester resin.

The acid anhydride-based compound may be a cyclic unsaturated acid anhydride-based compound having 4 to 6 carbon atoms.

The core layer may include 90% by weight or more of the polyester resin.

The polyester resin may include a linear diol-based repeating unit having 3 to 7 carbon atoms.

The polyester resin may include 15 to 55 mol% of the linear diol-based repeating unit having 3 to 7 carbon atoms relative to the total diol-based repeating unit.

The polyester resin may include a dicarboxylic acid-based repeating unit.

The polyester resin may include 15 to 50 mol% of isophthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units.

The glass fiber composite material according to another embodiment of the present specification includes a skin layer and a core layer positioned on the skin layer.

The skin layer includes a fiberglass fabric.

The core layer has a peel strength value of 950 gf/inch or more when peeled from the glass fiber fabric at a peel rate of 152 mm/min.

The method for manufacturing a film for a glass fiber composite material according to another embodiment of the present specification is a preparation step of preparing a polyester resin melt by polymerizing a composition for a core layer comprising a dicarboxylic acid-based compound and a diol-based compound, the polyester A molding step of forming an acid-modified polyester resin melt by adding an acid anhydride-based compound to the resin melt, and extruding the acid-modified polyester resin melt to form an unstretched film; A stretching step of stretching, and a heat setting step of heat-setting the stretched film to prepare a core layer.

The core layer includes one surface and the other surface positioned opposite to the one surface.

The core layer is disposed so that one side is positioned on the glass fiber fabric, and after pressing at 260° C. and 1 MPa for 15 minutes, the peel strength value is 950 gf when peeled from the glass fiber fabric at a peel rate of 152 mm/min. /inch or larger.

The film for a glass fiber fabric composite material of the embodiment has excellent peel strength from the glass fiber fabric when attached to the glass fiber fabric by thermal pressure, and has a relatively low melting point and flowability is controlled when melting, making it easy to manufacture a composite material At the same time, it can have stable heat resistance and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram explaining the method of measuring the peeling strength of a core layer.
2 is a conceptual diagram illustrating a glass fiber fabric composite material according to an embodiment of the present specification.
3 is a conceptual diagram illustrating a glass fiber fabric composite material according to another embodiment of the present specification.

Hereinafter, the embodiments will be described in detail so that those of ordinary skill in the art can easily carry out the embodiments. However, the embodiment may be implemented in various different forms and is not limited to the embodiment described herein.

As used herein, the terms "about," "substantially," and the like, are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of embodiments. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way.

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.

Throughout this specification, reference to “A and/or B” means “A, B, or A and B”.

Throughout this specification, terms such as “first”, “second” or “A” and “B” are used to distinguish the same terms from each other unless otherwise specified.

In this specification, the meaning that B is located on A means that B is located on A or B is located on A while another layer is located in between, and B is located in contact with the surface of A It is not construed as being limited to

In the present specification, unless otherwise specified, the expression “a” is interpreted as meaning including “a” or “plural” as interpreted in context.

In the present specification, room temperature means 20 to 25 °C.

The glass fiber fabric composite material may be manufactured by disposing a film on the glass fiber fabric and then impregnating the film by pressing the film toward the glass fiber fabric at a high temperature. Specifically, the film is melted due to the high temperature atmosphere, and the lower portion of the melted film may be impregnated into the space formed between the glass fibers in the glass fiber fabric due to the pressure. Thereafter, the composite material can be manufactured by curing the molten film by lowering the temperature.

The manufactured composite material may be processed into a predetermined shape through heating. It can be processed to have a preset shape by applying a force after melting or softening some of the film included in the composite material through heating. If the melting point of the film included in the composite material is not controlled, the processability of the composite material may be reduced in a low-temperature atmosphere, and the heat resistance and mechanical properties of the manufactured film and the composite material including the film do not have the desired properties. it may not be In addition, if the adhesive force of the film included in the composite material is not controlled, the film may be peeled off from the glass fiber fabric in the process of applying a force on the surface of the composite material for shape processing.

The inventors of the embodiment control the melting point of the film and the flow index at the time of melting, and by controlling the adhesive force between the polymer resin layer and the glass fiber fabric, it is possible to provide a film for a composite material that has excellent mechanical properties and is easy to process, The implementation was completed.

Hereinafter, the present embodiments will be described in more detail.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram explaining the method of measuring the peeling strength of a core layer.

An embodiment will be described in detail below with reference to FIG. 1 .

In order to achieve the above object, the film for a glass fiber fabric composite material according to an embodiment disclosed herein includes a core layer (20).

The core layer 20 is a layer bonded to the glass fiber fabric 11 when manufacturing the glass fiber fabric composite material. When the glass fiber fabric composite material is manufactured, one side of the core layer 20 is disposed so that it is positioned on the glass fiber fabric 11, and then the side portion of the one side of the core layer 20 melted through a heating and pressing process is a glass fiber fabric (11) By being impregnated to the side, the core layer 20 may be bonded to the glass fiber fabric 11 .

The core layer 20 may include a polyester resin. The polyester resin may have a melting point of 210 to 245°C.

When the melting point of the polyester resin included in the core layer 20 is within the above range, processability and heat resistance of the core layer 20 may be improved together. Specifically, by controlling the melting point of the core layer 20, the core layer 20 is sufficiently melted even at a relatively low temperature in the impregnation process to facilitate processing of the shape of the composite material including the core layer 20 and at the same time The composite material including the layer 20 may have stable durability in a high-temperature environment.

The melting point of the polyester resin is measured using a differential scanning calorimeter by annealing the polyester resin to be measured at 300° C. for 5 minutes, cooling it to room temperature, and setting the temperature increase rate to 0.1° C./10 min. The melting point of the polyester resin may be exemplarily measured through a DSC 2500 model manufactured by TA Instruments.

The polyester resin may have a melting point of 210 to 245°C. The polyester resin may have a melting point of 220 to 240°C. The polyester resin may have a melting point of 225 to 235°C. In this case, the composite material including the core layer 20 may have heat resistance above a certain standard while being easy to process.

The polyester resin may have a melt index of 20 to 80 g/10min at 250°C.

The polyester resin may have a melt index of 20 to 80 g/10 min at 250° C. and 2.16 kg.

The core layer 20 may be impregnated into a space formed between the woven glass fibers of the glass fiber fabric 11 by melting at least a portion thereof in a high temperature atmosphere. If the flowability of the molten core layer 20 is not controlled, the degree of impregnation of the molten core layer 20 from the surface of the glass fiber fabric 11 in the thickness direction decreases, so that the film for the composite material in the manufactured composite material is unstable. A problem with peeling force may occur. On the other hand, if the flowability of the molten core layer 20 is excessively high, it may be difficult to control the thickness uniformity of the core layer 20 when the core layer 20 is manufactured through melt extrusion. Therefore, by controlling the flowability of the polyester resin included in the core layer 20 when melting, the core layer 20 can have a sufficient degree of impregnation to have excellent peeling force and at the same time, the core layer 20 ) can improve the thickness uniformity.

The melt index of the polyester resin is measured according to ASTM D1238 at 250°C and 2.16 kg.

The polyester resin may have a melt index of 20 to 80 g/10min at 250°C. The polyester resin may have a melt index of 30 to 60 g/10min at 250°C. The polyester resin may have a melt index of 35 to 55 g/10min at 250°C. The polyester resin may have a melt index of 20 to 80 g/10 min at 250° C. and 2.16 kg. The polyester resin may have a melt index of 30 to 60 g/10 min at 250° C. and 2.16 kg. The polyester resin may have a melt index of 35 to 55 g/10 min at 250° C. and 2.16 kg. In this case, the core layer 20 impregnated in the glass fiber fabric 11 has sufficient peel strength, and the core layer 20 having a uniform thickness can be obtained.

In the core layer 20, the melting point and the melt index may be controlled at the same time. Even if the melting point of the core layer 20 is controlled and melting and impregnation at a low temperature is possible, if the melt index does not have a sufficient value, the amount of the core layer 20 impregnated in the glass fiber fabric in the thickness direction may not be sufficient. In this case, the peel strength of the core layer 20 from the glass fiber fabric 11 is lowered, so that the core layer 20 may not have the desired effect.

The core layer 20 includes one surface and the other surface positioned opposite to the one surface.

The core layer 20 is pressed to the glass fiber fabric 11 at 260° C. and 1 MPa for 15 minutes, and then peeled from the glass fiber fabric 11 at a peeling rate of 152 mm/min. The peel strength value is 950 gf /inch or larger.

After the glass fiber fabric composite material is disposed in contact with one side of the core layer 20 on the glass fiber fabric 11 , the core layer 20 has a high temperature, specifically, the softening point of the resin contained in the core layer 20 . Alternatively, at least a portion of the core layer 20 is melted by applying a temperature above the melting point, and a certain pressure is applied to or reduced in pressure to the core layer 20 or the glass fiber fabric 11 to form a molten portion of the core layer 20 ( It can be manufactured by impregnating and curing the glass fiber fabric 11 side. If the peel strength of the core layer 20 is stronger when peeling the core layer 20 from the glass fiber fabric 11 after at least a part is impregnated and cured, glass that may occur in the shape processing process of the glass fiber fabric composite material It is possible to better prevent the fibrous fabric from falling off, and the composite material can have more stable durability.

The glass fiber fabric 11 applied when measuring the peel strength of the core layer 20 may be a woven glass fiber fabric or a non-woven glass fiber fabric.

The woven glass fiber fabric may be a glass fiber fabric woven using glass fibers as weft and/or warp yarns. Woven roving can be applied to the woven glass fiber fabric.

The woven glass fiber fabric may be woven in the form of a plain weave. In this case, air bubbles generated during impregnation of the one-surface side portion of the core layer can be easily removed.

The weight per unit area of the woven glass fiber fabric may be 450 to 700 g/m ² . The weight per unit area of the woven glass fiber fabric may be 500 to 650 g/m ² . The weight per unit area of the woven glass fiber fabric may be 530 to 610 g/m ² . In this case, the space for impregnation in the glass fiber fabric is controlled, and the impregnation workability is improved by controlling the degree of impregnation of the one side part of the core layer to the glass fiber fabric side, and the interlayer peel strength of the manufactured glass fiber fabric composite material is improved. can

The woven glass fiber fabric may be exemplarily applied to Owens Corning's WR570-100.

The non-woven type glass fiber fabric is a non-woven type glass fiber fabric in which glass fibers cut to a certain size are dispersed and compressed using an adhesive. For non-woven fiberglass fabrics, ?h strand mat (chopped strand mat) can be applied.

The peel strength of the core layer 20 is measured according to ASTM D903. Specifically, one side of the core layer 20 is disposed on the glass fiber fabric 11, and the composite material specimen is prepared by pressing at 260° C. and 1 MPa for 15 minutes. When manufacturing the composite material specimen, some surfaces including the ends of the core layer 20 are pressed so as not to be attached to the glass fiber fabric. Thereafter, the surface on which the glass fiber fabric 11 of the composite material is positioned is fixed to the alignment plate 202 . After fixing the end of the portion of the core layer 20 that is not attached to the glass fiber fabric 11 to the core layer fixing grip 201, the core layer fixing grip 201 is rotated 180 degrees with the glass fiber fabric 11 The peel strength of the core layer 20 is measured while moving at a peeling speed of 152 mm/min by setting the moving direction D _p to form.

The core layer 20 is disposed so that one side is positioned on the glass fiber fabric 11, and after pressing at 260° C. and 1 MPa for 15 minutes, peeled from the glass fiber fabric 11 at a peeling rate of 152 mm/min. Peel strength values may be greater than or equal to 950 gf/inch. The peel strength value may be greater than or equal to 1000 gf/inch. The peel strength value may be greater than or equal to 1100 gf/inch. The peel strength value may be 3000 gf/inch or less. The peel strength value may be less than or equal to 2000 gf/inch. The peel strength value may be 1500 gf/inch or less. In this case, the glass fiber composite material including the core layer 20 can suppress the occurrence of defects due to long-term use.

The core layer 20 may have a TD value of Equation 1 below 5% or less.

[Equation 1]

In Equation 1, the T _max is the maximum thickness of the core layer 20 , the T _min is the minimum thickness of the core layer 20 , and the T _ave is the average thickness of the core layer 20 .

The thickness of the core layer 20 is required to be controlled within a certain range. In this case, when the core layer 20 is impregnated on the glass fiber fabric 11, the uniformity of the degree of impregnation in the in-plane direction can be improved, so that the durability of the composite material can be improved, and the composite including the core layer 20 The thickness deviation in the in-plane direction of the material may be uniform.

When measuring the TD value of the core layer 20, after measuring the thickness of the core layer 20 at 50 points at intervals of 5 cm in the longitudinal and transverse directions of the core layer 20, T _max from the thickness value, Derive T _min , T _ave and TD values.

The core layer 20 may have a TD value of 5% or less. The core layer 20 may have a TD value of 0% or more. In this case, the deviation in peel strength in the in-plane direction of the core layer 20 and the deviation in thickness in the in-plane direction of the composite material may be controlled to be less than or equal to a predetermined value.

The thickness of the core layer 20 may be 30 to 100 μm. The thickness of the core layer 20 may be 35 to 70 um. The thickness of the core layer 20 may be 40 to 55 μm. In this case, a portion of one side of the core layer is impregnated into the glass fiber fabric to a preset extent, so that the core layer may have excellent peel strength, and the glass fiber fabric composite material including the core layer may have stable durability.

The polyester resin may include an acid-modified polyester resin.

The acid-modified polyester resin may be a polyester resin grafted with an acid anhydride-based compound.

The polyester resin may include 0.1 to 0.5 parts by weight of a functional group derived from the acid anhydride-based compound based on 100 parts by weight of the polyester resin.

The core layer 20 may have different peeling force depending on the repeating unit, functional group, and weight average molecular weight of the resin included in the resin at the same degree of impregnation in the thickness direction. Specifically, in order to improve the adhesive properties between the polyester resin contained in the core layer 20 and the glass fiber fabric 11, the polyester resin contains an acid-modified polyester resin, so that the core layer 20 is a glass fiber fabric. It can have excellent peeling force from (11).

The acid-modified polyester resin may be a polyester resin grafted with an acid anhydride-based compound. The acid anhydride-based compound may be grafted onto the polyester resin chain. The acid anhydride-based compound may be grafted to the end of the polyester resin chain.

When the acid-modified polyester resin contains a functional group derived from an acid anhydride-based compound, the core layer 20 is formed of the glass fiber fabric 11 due to the interaction between the functional group and the hydroxyl group contained on the surface of the glass fiber fabric 11 . It can have a better peel strength when peeled from. However, when an acid anhydride-based compound exceeding a preset range is added to the molten resin composition in order to increase the degree of grafting of the acid anhydride-based compound, the thickness uniformity of the core layer 20 may be reduced. Accordingly, the inventors of the embodiment control the content of the functional group derived from the acid anhydride-based compound in the polyester resin when the core layer 20 is formed, so that when the core layer 20 is peeled from the glass fiber fabric 11, the core layer 20 ), while improving the peel strength, it was also confirmed that it is possible to provide a film for a composite material in which the thickness uniformity is controlled within a certain range.

The acid anhydride-based compound may be a cyclic unsaturated acid anhydride-based compound having 4 to 6 carbon atoms. As the acid anhydride-based compound, maleic anhydride may be used.

The polyester resin may include 0.1 to 0.5 parts by weight of a functional group derived from the acid anhydride-based compound based on 100 parts by weight of the polyester resin. The polyester resin may include 0.15 to 0.4 parts by weight of a functional group derived from the acid anhydride-based compound based on 100 parts by weight of the polyester resin. The polyester resin may include 0.17 to 0.35 parts by weight of a functional group derived from the acid anhydride-based compound based on 100 parts by weight of the polyester resin. In this case, the core layer 20 may have a controlled thickness uniformity while exhibiting excellent peel strength from the glass fiber fabric 11 .

The core layer 20 may include 90% by weight or more of the polyester resin. The core layer 20 may include 95% by weight or more of the polyester resin.

Composition of polyester resin

The polyester resin may include a diol-based repeating unit and a dicarboxylic acid repeating unit.

The polyester resin may include a linear diol-based repeating unit having 3 to 7 carbon atoms. Specifically, the linear diol-based repeating unit having 3 to 7 carbon atoms includes 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and these It may be a repeating unit derived from a diol-based compound selected from the group consisting of a combination of

The polyester resin may include a linear diol-based repeating unit having 4 to 6 carbon atoms. Specifically, the linear diol-based repeating unit having 4 to 6 carbon atoms is a repeating unit derived from a diol-based compound selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and combinations thereof. It can be a unit.

The polyester resin may include a 1,4-butanediol-based repeating unit.

When the linear diol-based repeating unit is included in the polyester resin, the melting point and melt index of the polyester resin are controlled, so that the core layer 20 can be smoothly impregnated into the glass fiber fabric 11 .

The polyester resin may contain 15 to 55 mol% of a linear diol-based repeating unit having 3 to 7 carbon atoms based on the total diol-based repeating unit. The polyester resin may contain 20 to 45 mol% of a linear diol-based repeating unit having 3 to 7 carbon atoms relative to the total diol-based repeating unit. The polyester resin may contain 30 to 40 mol% of a linear diol-based repeating unit having 3 to 7 carbon atoms relative to the total diol-based repeating unit.

The polyester resin may contain 15 to 55 mol% of a linear diol-based repeating unit having 4 to 6 carbon atoms relative to the total diol-based repeating unit. The polyester resin may contain 20 to 45 mol% of a linear diol-based repeating unit having 4 to 6 carbon atoms relative to the total diol-based repeating unit. The polyester resin may contain 30 to 40 mol% of a linear diol-based repeating unit having 4 to 6 carbon atoms relative to the total diol-based repeating unit.

The polyester resin may contain 15 to 55 mol% of 1,4-butanediol-based repeating units based on the total diol-based repeating units. The polyester resin may contain 20 to 45 mol% of 1,4-butanediol-based repeating units based on the total diol-based repeating units. The polyester resin may contain 30 to 40 mol% of 1,4-butanediol-based repeating units based on the total diol-based repeating units.

In this case, the core layer 20 may be smoothly impregnated even at a low temperature, and the composite material including the core layer 20 may have stable heat resistance and durability.

The polyester resin may further include another diol-based repeating unit in addition to the linear diol-based repeating unit having 3 to 7 carbon atoms. The other diol-based repeating unit further included may be a repeating unit derived from ethylene glycol, but is not limited thereto.

The polyester resin may include 15 to 50 mol% of isophthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units. The isophthalic acid-based repeating unit is a repeating unit derived from an isophthalic acid-based compound,

The polyester resin may include 15 to 50 mol% of isophthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units. The polyester resin may contain 20 to 45 mol% of isophthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units. The polyester resin may contain 25 to 40 mol% of isophthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units. In this case, it is possible to easily impregnate and process the core layer 20 at a low temperature by controlling the crystallinity of the polyester resin, and heat resistance may be maintained at a certain level or more.

The polyester resin may further include another dicarboxylic acid-based repeating unit in addition to the isophthalic acid-based repeating unit. Specifically, the polyester resin is composed of terephthalic acid, dimethyl terephthalate, naphthalenedicarboxylic acid, orthophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, esters thereof, and combinations thereof. It may further include a repeating unit derived from any one selected from the group.

The polyester resin may include a terephthalic acid-based repeating unit. The polyester resin may include 40 to 85 mol% of the terephthalic acid-based repeating unit relative to the total dicarboxylic acid-based repeating unit. The polyester resin may include 50 to 80 mol% of terephthalic acid-based repeating units relative to the total dicarboxylic acid-based repeating units.

The polyester resin may be an acid-modified polyester resin. The acid-modified polyester resin is a polyester resin in which an acid anhydride-based compound is grafted onto a polyester resin. The acid-modified polyester resin may include an acid anhydride-based functional group. The description of the acid-modified polyester resin is omitted because it overlaps with the contents described above.

Polyester resin composition for core layer

The polyester resin composition may include a diol-based compound and a dicarboxylic acid-based compound.

The polyester resin composition may include a linear diol-based compound having 3 to 7 carbon atoms. Specifically, the linear diol-based compound having 3 to 7 carbon atoms includes 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and these It may be a diol-based compound selected from the group consisting of combinations.

The polyester resin composition may include a linear diol-based compound having 3 to 7 carbon atoms. The polyester resin composition may contain 15 to 55 mol% of a linear diol-based compound having 3 to 7 carbon atoms relative to the total diol-based compound. The polyester resin composition may contain 20 to 45 mol% of a linear diol-based compound having 3 to 7 carbon atoms relative to the total diol-based compound. The polyester resin composition may contain 30 to 40 mol% of a linear diol-based compound having 3 to 7 carbon atoms based on the total diol-based repeating units.

The polyester resin composition may contain 15 to 55 mol% of a linear diol-based compound having 4 to 6 carbon atoms relative to the total diol-based compound. The polyester resin composition may contain 20 to 45 mol% of a linear diol-based compound having 4 to 6 carbon atoms relative to the total diol-based compound. The polyester resin composition may contain 30 to 40 mol% of a linear diol-based compound having 4 to 6 carbon atoms relative to the total diol-based compound.

The polyester resin composition may contain 15 to 55 mol% of 1,4-butanediol based on the total diol-based compound. The polyester resin composition may contain 20 to 45 mol% of 1,4-butanediol based on the total diol-based compound. The polyester resin composition may contain 30 to 40 mol% of 1,4-butanediol based on the total diol-based compound.

In this case, the core layer 20 manufactured from the polyester resin composition may have stable heat resistance and durability of the composite material including the core layer 20 while improving processability and productivity in a low-temperature atmosphere.

The polyester resin composition may include other diol-based compounds in addition to the linear diol-based compound having 3 to 7 carbon atoms. As the other diol-based compound, ethylene glycol may be used for example, but is not limited thereto.

The polyester resin composition may include isophthalic acid. The polyester resin composition may contain 15 to 50 mol% of isophthalic acid relative to the total dicarboxylic acid-based compound. The polyester resin composition may contain 20 to 45 mol% of isophthalic acid relative to the total dicarboxylic acid-based compound. The polyester resin composition may contain 25 to 40 mol% of isophthalic acid relative to the total dicarboxylic acid-based compound. In this case, the degree of crystallinity of the resin prepared from the polyester resin composition is adjusted to improve the processability of the core layer 20 including the resin, and the composite material may have stable heat resistance.

The polyester resin composition may further include other dicarboxylic acid-based compounds in addition to isophthalic acid. Specifically, the polyester resin composition includes terephthalic acid, dimethyl terephthalate, naphthalenedicarboxylic acid, orthophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, esters thereof, and combinations thereof. It may further include any one selected from the group consisting of.

The polyester resin composition may include a terephthalic acid-based compound. The polyester resin composition may contain 40 to 85 mol% of terephthalic acid relative to the total dicarboxylic acid-based compound. The polyester resin composition may contain 50 to 80 mol% of terephthalic acid relative to the total dicarboxylic acid-based compound.

The polyester resin composition may include an acid anhydride-based compound. The description of the acid anhydride-based compound is omitted because it overlaps with the previous description.

In addition to the above-mentioned diol-based compound, dicarboxylic acid-based compound and acid anhydride-based compound, the polyester resin composition includes a plasticizer, a filler, a lubricant, an antibacterial agent, a processing aid, and an anti-blocking agent. It may further include additives such as a flame retardant, a stabilizer, and a polymerization catalyst. The additive can be applied without limitation as long as it is applied to the polyester resin composition.

Core layer manufacturing method

The method for manufacturing a film for a glass fiber composite material includes a preparation step of preparing a polyester resin melt by polymerizing a composition for a core layer containing a dicarboxylic acid-based compound and a diol-based compound, and adding an anhydride-based compound to the polyester resin melt. A molding step of forming a modified polyester resin melt and extruding the acid-modified polyester resin melt to form an unstretched film, a stretching step of stretching the unstretched film in the longitudinal and transverse directions, and heat setting the stretched film to core and a heat setting step to prepare the layer.

In the preparation step, a composition for a core layer containing a diol-based compound and a dicarboxylic acid-based compound is introduced into the reactor, and the reactor temperature is set to 200 to 300°C under a pressure of 1 to 4 kg/cm ² , and the diol-based compound and the dicarboxylic acid The compound can be esterified. As the atmospheric gas applied to form a pressure of a certain size in the reactor, a gas having low reactivity, for example, N ₂ may be applied to suppress the occurrence of side reactions.

After the esterification reaction is completed, additives such as a stabilizer, an antiblocking agent, and a polymerization catalyst may be added into the reactor.

Thereafter, after adjusting the pressure inside the reactor to a vacuum state of 0.3 Torr or less, the temperature of the reactor is set to 250 to 400° C. to obtain a polyester resin melt from the esterified reactant.

In the molding step, an acid-modified polyester resin melt may be formed by adding 0.1 to 0.5 wt% of an acid anhydride-based compound as an additive to the polyester resin.

The acid-modified polyester resin melt is melt-extruded at 240 to 300° C. and adhered to a cooling roll at 10 to 40° C. through a conventional T-die to prepare an amorphous sheet having a thickness of 10 to 200 μm.

In the stretching step, the amorphous sheet may be longitudinally stretched using a stretching roll in an atmosphere of 50 to 150°C. The longitudinal stretch may be stretched 1.1 to 1.5 times.

In the heat setting step, the sheet after stretching in the longitudinal and transverse directions may be heat-set at a temperature of 100 to 180° C. and then undergo a relaxation process to prepare the core layer 20 .

The description of the core layer 20 manufactured by the above method is omitted because it overlaps with the above-described content.

2 is a conceptual diagram illustrating a glass fiber fabric composite material according to an embodiment of the present specification. 3 is a conceptual diagram illustrating a glass fiber composite material according to another embodiment of the present specification.

The embodiment will be described in detail below with reference to FIGS. 2 and 3 .

The glass fiber composite material 100 according to another embodiment of the present specification includes a skin layer 10 and a core layer 20 positioned on the skin layer 10 . The skin layer 10 includes a fiberglass fabric. The core layer 20 has a peel strength value of 950 gf/inch or more when peeled from the glass fiber fabric at a peel rate of 152 mm/min.

The glass fiber composite material 100 may further include another layer positioned on the core layer 20 . The glass fiber composite material 100 may further include a skin layer 10 positioned on the core layer 20 .

The description of the film for the glass fiber fabric composite material and the glass fiber fabric is omitted because it overlaps with the contents described above.

Hereinafter, the invention of the embodiment will be described in more detail through specific examples. The following examples are only examples for helping understanding of the embodiments, and the scope of the present invention is not limited thereto.

Preparation Example: Preparation of polyester resin

The diol-based compound and the dicarboxylic acid-based compound in the amounts shown in Table 1 below according to Examples and Comparative Examples were introduced into a 30L reactor in a molar ratio of 1:1. Thereafter, the esterification reaction was performed by setting the reactor temperature to 255° C. under a nitrogen pressure of 2.0 kgf/cm ² . Thereafter, the esterified reactant was polymerized at 285° C. in a vacuum of 0.3 Torr or less to obtain a polyester resin.

Preparation Example: Preparation of the core layer

1) Examples 1 to 3 and Comparative Examples 1 to 4

0.3 parts by weight of maleic anhydride was added to 100 parts by weight of the polyester resin prepared above, melt-extruded at 260° C., and adhered to a cooling roll cooled to 30° C. through a T-die to obtain an amorphous sheet having a thickness of 70 μm. The amorphous sheet was continuously stretched 1.4 times by passing through a stretching roll in an atmosphere of 80° C., and then heat treatment and 2% relaxation process were performed at 130° C. to obtain a core layer having a thickness of 50 μm.

2) Example 4

Example 4 was prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 4, but maleic anhydride in the polyester resin was not added.

3) Comparative Example 5

Comparative Example 5 was prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 4, except that 1.0 parts by weight of maleic anhydride was added to 100 parts by weight of the polyester resin.

Dicarboxylic acid compound (mol%) Diol compound (mol%) Maleic anhydride (parts by weight) terephthalic acid isophthalic acid ethylene glycol butanediol Example 1 60 40 60 40 0.3 Example 2 70 30 60 40 0.3 Example 3 80 20 70 30 0.3 Example 4 60 40 60 40 - Comparative Example 1 90 10 70 30 0.3 Comparative Example 2 80 20 90 10 0.3 Comparative Example 3 60 40 40 60 0.3 Comparative Example 4 90 10 90 10 0.3 Comparative Example 5 60 40 60 40 One

In Table 1, the terephthalic acid content means the terephthalic acid content compared to the total dicarboxylic acid-based compounds, the isophthalic acid content means the isophthalic acid content compared to the total dicarboxylic acid-based compounds, and the ethylene glycol content is the ethylene glycol content compared to the total dicarboxylic acid-based compounds Meaning, the butanediol content refers to the butanediol content compared to the total diol-based compounds.

Evaluation Example: Physical Properties of Polyester Resins

1) Melting point of polyester resin

The polyester resin specimens of Examples and Comparative Examples were annealed at 300° C. for 5 minutes and then cooled to room temperature. Thereafter, the melting point of each specimen was measured by scanning after setting the temperature increase rate to 0.1° C./min using the DSC 2500 model manufactured by TA Instruments. Melting point values measured in Examples and Comparative Examples are shown in Table 2 below.

2) Polyester resin melt index

The melt index of the polyester resin specimens of Examples and Comparative Examples was measured at 250° C. according to ASTM D1238. The measured values are shown in Table 2 below.

Evaluation example: physical properties of the core layer

1) Measurement of peel strength of the core layer

The core layer specimens of Examples and Comparative Examples were attached to the glass fiber fabric of Owens Corning's WR570-100 model. Specifically, after arranging the core layer specimens of Examples and Comparative Examples on the glass fiber fabric, a hot-press process was performed at 260° C. and 1 MPa conditions.

Thereafter, the peel strength of the attached specimen was measured according to ASTM D903. The measured values are shown in Table 2 below.

2) Measuring the thickness uniformity of the core layer

In the core layer specimens of Examples and Comparative Examples, 50 points were set at intervals of 5 cm in the longitudinal and transverse directions, respectively, and the thickness of the core layer was measured at each point. TD was calculated by deriving T _max , T _min , and T _ave of Equation 1 from the thickness measurement value of each point.

For each Example and Comparative Example, when the TD value is 5% or less, ◎, when the TD value is more than 5% and less than 10% ○, when the TD value is more than 10% and less than 15% △, when the TD value is 15% or less Table 2 below.

Melting point (℃) Melt index (g/10min) Peel strength (gf/inch) thickness uniformity Example 1 222 45 1180 ◎ Example 2 228 42 1110 ◎ Example 3 235 38 1050 ◎ Example 4 222 45 980 ◎ Comparative Example 1 249 13 690 △ Comparative Example 2 244 15 820 ○ Comparative Example 3 204 90 1180 △ Comparative Example 4 255 7 530 △ Comparative Example 5 222 45 1050 △

In Table 2, in the case of melting points, Examples 1 to 4 showed 210 to 240 °C, Comparative Examples 1, 2, and 4 had a melting point of more than 240 °C, Comparative Example 3 showed less than 210 °C .

In the case of melt index, Examples 1 to 4 exhibited 30 to 50 g/10 min, but Comparative Examples 1 to 4 exhibited less than 30 g/10 min or more than 80 g/10 min.

In the case of peel strength, Examples 1 to 4 showed a value of 950 gf/inch or more, but Comparative Examples 1, 2, and 4 showed a value of less than 950 gf/inch.

In the case of thickness uniformity, Examples 1 to 4 were evaluated as ◎, but all Comparative Examples received lower uniformity evaluation than Examples.

Although the preferred embodiment has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the embodiment defined in the following claims are also within the scope of the present invention. will belong

100: glass fiber fabric composite material
10: skin layer
11: Glass fiber fabric
20: core layer
200: peel strength meter
201: core layer fixing grip
202: alignment plate
Dp: Core layer fixed grip movement direction

Claims (10)

comprising a core layer;
The core layer includes a polyester resin,
The polyester resin has a melting point of 210 to 245° C., and a melt index of 20 to 80 g/10 min at 250° C., a film for a glass fiber composite material.
According to claim 1,
The core layer includes one surface and the other surface positioned opposite to the one surface.
The core layer is disposed so that one side of the core layer is positioned on a glass fiber fabric, and after pressing at 260° C. and 1 MPa for 15 minutes, peel strength ( Peel strength) value of 950 gf/inch or higher, a film for glass fiber composite materials.
According to claim 1,
The core layer has a TD value of 5% or less in Equation 1 below, a film for a glass fiber composite material;
[Equation 1]

In Equation 1 above,
The T _max is the maximum thickness of the core layer, the T _min is the minimum thickness of the core layer, the T _ave is the average thickness of the core layer.
The method of claim 1,
The polyester resin includes an acid-modified polyester resin,
The acid-modified polyester resin is a polyester resin grafted with an acid anhydride-based compound,
The polyester resin comprises 0.1 to 0.5 parts by weight of a functional group derived from an acid anhydride-based compound based on 100 parts by weight of the polyester resin, a film for a glass fiber composite material.
5. The method of claim 4,
The acid anhydride-based compound is a cyclic unsaturated acid anhydride-based compound having 4 to 6 carbon atoms, a film for a glass fiber fabric composite material.
The method of claim 1,
The core layer comprises at least 90% by weight of the polyester resin, a film for a glass fiber composite material.
The method of claim 1,
The polyester resin includes a linear diol-based repeating unit having 3 to 7 carbon atoms, and 15 to 55 mol% of the linear diol-based repeating unit having 3 to 7 carbon atoms relative to the total diol-based repeating unit. Film for composite materials.
According to claim 1,
The polyester resin includes a dicarboxylic acid-based repeating unit, and 15 to 50 mol% of an isophthalic acid-based repeating unit relative to the total dicarboxylic acid-based repeating unit, a film for a glass fiber composite material.
A skin layer and a core layer positioned on the skin layer,
The skin layer includes a glass fiber fabric,
The core layer includes a polyester resin,
The polyester resin has a melting point of 210 to 245° C., and a melt index of 20 to 80 g/10 min at 250° C., a glass fiber composite material.
A preparation step of preparing a polyester resin melt by polymerizing a composition for a core layer including a dicarboxylic acid-based compound and a diol-based compound;
a molding step of adding an acid anhydride-based compound to the polyester resin melt to form an acid-modified polyester resin melt, and extruding the acid-modified polyester resin melt to form an unstretched film;
a stretching step of stretching the unstretched film in the longitudinal and transverse directions; and
Including; heat setting step of heat setting the stretched film to prepare a core layer;
The core layer includes a polyester resin,
The polyester resin has a melting point of 210 to 245° C., and a melt index of 20 to 80 g/10 min at 250° C., a method for manufacturing a film for a glass fiber composite material.

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