Enhanced styrene-ethylene-butylene-styrene (SEBS) / thermoplastic polyurethane (TPU) blends for continuous bonding operations

Abstract

An automatic continuous bonding system comprising: a first roller for controlling the speed and tension of an adhesive tape comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer mixed with 5 wt% to 20 wt% of aromatic polyester thermoplastic polyurethane (TPU); the second roller is used for controlling the speed and tension of the fabric; and a heated air nozzle that generates heated air that melts the adhesive tape onto a fabric passing between the first roller and the second roller.

Description

[0001] Inventors:

[0002] E.Bermejo

[0003] applicant

[0004] Bixby International Inc.

[0005] Government Interest Statement

[0006] none.

[0007] CROSS-REFERENCE TO RELATED APPLICATIONS

[0008] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 390,807, filed on July 20, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0009] The present invention relates generally to polymeric materials and, more particularly, to reinforced styrene-ethylene-butylene-styrene (SEBS) / thermoplastic polyurethane (TPU) blends for use in continuous bonding operations.

[0010] Usually, styrene-ethylene-butylene-styrene (also known as SEBS) is an important thermoplastic elastomer (TPE), which has properties similar to rubber, but does not need to be vulcanized. SEBS has strength and flexibility, has excellent heat and UV tolerance, and is easy to process. It is prepared by partial and selective hydrogenation of styrene-butadiene-styrene copolymer (SBS), which improves thermal stability, weather resistance and oil resistance, and makes SEBS steam sterilizable. However, hydrogenation also reduces mechanical properties and increases the cost of polymers. SEBS elastomers are usually blended with other polymers to enhance their performance.

[0011] Thermoplastic polyurethane (TPU) is a thermoplastic elastomer block copolymer composed of alternating hard and soft segments or domains formed by the reaction of three structural segments (polyol, diisocyanate, and chain extender or short chain diol). TPU materials are tough, flexible, durable, and resistant to abrasion, such as oil and lubricants. The unique blend of three structural segments makes it suitable for a variety of applications in automotive, sports and textile coatings, breathable membranes, etc.

[0012] TPU has excellent load bearing capacity, high elongation at break and excellent tensile strength. The blend can be used as soft engineering plastics and soft rubbers – with different intrinsic hardness ranges (Shore 30A – Shore 100A). TPU materials are also used as high-quality additives for other thermoplastics (such as polycarbonate and ABS) to improve their toughness and elongation. Summary of the invention

[0013] The following is a simplified summary of the innovation to provide a basic understanding of some aspects of the present invention. This summary is not a comprehensive description of the present invention. Its intention is neither to identify the main or key elements of the present invention nor to delimit the scope of the present invention. Its sole purpose is to introduce some concepts of the present invention in a simplified form as a prelude to a more detailed description later.

[0014] In one aspect, the present invention provides an adhesive composition comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer mixed with 5 wt % to 20 wt % of an aromatic polyester thermoplastic polyurethane (TPU).

[0015] In another aspect, the present invention provides an automatic continuous bonding system comprising: a first roller for controlling the speed and tension of an adhesive tape comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer mixed with 5 wt%-20 wt% of an aromatic polyester thermoplastic polyurethane (TPU); a second roller for controlling the speed and tension of a fabric; and a heated air nozzle for generating heated air to melt the adhesive tape onto the fabric passing between the first roller and the second roller.

[0016] In yet another aspect, the present invention provides an adhesive composition comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer mixed with 5 to 20 wt % of an aromatic polyether thermoplastic polyurethane.

[0017] In yet another aspect, the present invention provides an automated continuous bonding system comprising: a first roller for controlling the speed and tension of an adhesive tape comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer mixed with 5 wt % to 20 wt % of an aromatic polyether thermoplastic polyurethane; a second roller for controlling the speed and tension of a fabric; and a heated air nozzle for generating heated air to melt the adhesive tape onto the fabric passing between the first roller and the second roller.

[0018] Embodiments of the invention may have one or more of the following advantages.

[0019] The present invention requires long-term durability at high elongation and resilience.

[0020] The present invention cannot be a pressure sensitive adhesive because it relies on having a solid elastic resilience at high elongation.

[0021] The present invention is not dependent on polyolefins and cannot use tackifiers.

[0022] The present invention utilizes conventional SEBS and conventional TPU to lower the activation temperature while maintaining the elasticity and resiliency of the strong adhesive tape.

[0023] The present invention does not rely on compatibilizing SEBS with TPU or making SEBS more polar.

[0024] The present invention is developed for adhesives and low activation temperatures (ie, low activation temperature elastic adhesive films).

[0025] The present invention is an unreacted homogeneous polymer blend.

[0026] The present invention does not require a new polymerization step, but rather utilizes conventional compounding of standard SEBS and TPU polymers to make the blend.

[0027] The present invention does not require transparency as a glass interlayer, nor does it require the ability to bond to a glass substrate; the present invention is opaque.

[0028] The present invention relies on SEBS as the primary component and TPU as a secondary additive to produce a strong film.

[0029] The present invention relies on a strong thermoplastic SEBS elastomeric primary phase modified with TPU.

[0030] The present invention produces a strong thermoplastic SEBS elastic film or band that utilizes TPU to change the surface activation temperature so as to adhere to curved and three-dimensional stretch fabrics during processing, while performing as a strong elastic waist band (or strap band) in the final application.

[0031] The present invention produces a strong, highly resilient elastic film that can be cut into strips (or "ribbons") for surface heat bonding to fabrics in a continuous low temperature textile assembly process. The ribbons bond stretch fabrics together, or attach to one side of a fabric, while becoming a strong, more comfortable, more resilient elastic band for securing garments (such as underwear, bras, sportswear, etc.) to the body.

[0032] These and other features and advantages will be apparent from a reading of the following detailed description and an overview of the associated drawings.It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of the aspects claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other aspects will now be described in detail with reference to the accompanying drawings, in which:

[0034] Figure 1An exemplary automated continuous bonding system is shown.

[0035] Figure 2 It's a table. DETAILED DESCRIPTION

[0036] The subject matter of the present invention is now described with reference to the accompanying drawings, wherein like reference numerals are used to refer to like elements throughout the text. In the following description, for the purpose of explanation, many specific details are listed to provide a comprehensive understanding of the present invention. However, it is clear that the present invention can be implemented without these specific details. In other cases, well-known structures and devices are shown in block diagram form to facilitate the description of the present invention.

[0037] Disclosed herein are various embodiments of materials including styrene-ethylene-butylene-styrene (SEBS) / thermoplastic polyurethane (TPU) blends. In some embodiments, the blends enhance the adhesive properties of styrene-ethylene-butylene-styrene (SEBS) block copolymers. SEBS does not have functional groups (e.g., -OH, -COOH, -OCOOR) that typically impart some "polarity" to the material. Adding functional groups to the SEBS block polymer increases its surface energy, thereby improving its "wettability" on the substrate and increasing the chance of producing chemical bonds. The disclosed blends can be used in a variety of applications, such as clothing and clothing, to name a few.

[0038] In one embodiment, the blending includes adding an aromatic polyester polyurethane to the SEBS by melt mixing. For example, during cast extrusion, adding up to about 10% of the aromatic polyester polyurethane by melt mixing improves the "wet out" of the hot melt adhesive on the substrate to adhere and form a strong chemical bond.

[0039] In one embodiment, using higher TPU loadings (eg, greater than about 20%) significantly impacts other unique and inherent properties of SEBS adhesives, including stretch and its subsequent recovery, to name a few.

[0040] Disclosed herein are various embodiments of materials comprising styrene-ethylene-butylene-styrene (SEBS) / thermoplastic polyurethane (TPU) blends supported by polyethylene terephthalate (PET), polyester, or paper carriers, to name a few. In one embodiment, the SEBS / TPU blend may be supported on a polar substrate. In another embodiment, the blend comprises primarily SEBS, with a small amount of TPU. In other words, the proportion of SEBS in the blend is greater than the proportion of TPU.

[0041] In one embodiment, the blending includes adding an aromatic polyester polyurethane to the SEBS block copolymer by melt mixing. In some embodiments, up to about 10% of the aromatic polyester polyurethane is added by melt mixing during calendering extrusion. In other embodiments, up to about 1%, or up to about 2%, or up to about 5% of the aromatic polyester polyurethane is added to the SEBS block copolymer by melt mixing during calendering extrusion. In these embodiments, the addition of the aromatic polyester polyurethane can improve the "wetting" of the hot melt adhesive on the substrate to bond and form a strong chemical bond.

[0042] In one embodiment, the blend includes a higher thermoplastic polyurethane (TPU) loading. For example, greater than about 20%. Higher TPU loading can affect the inherent adhesive properties of the SEBS block copolymer, thereby affecting the blend. In some cases, the amount of TPU can affect the stretchability and corresponding recoverability of the SEBS / TPU blend.

[0043] In some embodiments, the SEBS / TPU blend may include less than about 20% TPU loading, or less than about 10% TPU loading, or less than about 5% TPU loading, or less than about 2% TPU loading, or less than about 1% TPU loading.

[0044] In another embodiment, the wettability of SEBS on the applied substrate may be improved due to the increased surface energy.A small amount of TPU in a SEBS / TPU blend may not impair the functionality of the blend.

[0045] In some embodiments, the SEBS / TPU blend can be applied to the garment using a continuous bonding process. The presence of SEBS in the adhesive enhances properties such as weatherability, stretchability, and recovery, to name a few. In other embodiments, the SEBS / TPU blend can include polar functional groups, including but not limited to -OH, -COOH, -NH2. Adding these polar functional groups can further improve the wettability of the adhesive material to the substrate.

[0046] In one embodiment, when the SEBS / TPU blend is used as an adhesive for a continuous bonding process, TPU (eg, up to 20%) may be added to the blend to enhance other properties including but not limited to the stretch and recovery of the SEBS / TPU blend.

[0047] In one embodiment, the blend can reduce the glue line temperature (eg, activation temperature of the adhesive) of SEBS by adding TPU during the continuous bonding process.

[0048] In some embodiments, the blend can be processed using conventional equipment (e.g., extrusion or injection molding). In some embodiments, the blend can be calendered and extruded into a film roll with a suitable thickness. In other embodiments, the blend can be calendered and extruded into a sheet and die cut into any geometric shape or size of various thicknesses.

[0049] The presently disclosed embodiments can be used in a variety of applications, including application to clothing or garments, to name a few. In some embodiments, the disclosed SEBS / TPU blends can improve surface energy, wettability, transparency, elasticity and stretchability, among other enhancements. In other embodiments, the blends can reduce the bondline temperature of the SEBS (e.g., the activation temperature of the adhesive) for continuous bonding operations.

[0050] SEBS / TPU (styrene-ethylene-butadiene-styrene / thermoplastic polyurethane) thermoplastic elastomer blends are disclosed herein for use as continuous bonding adhesive tapes in the apparel industry.

[0051] Heat sealing tapes have proven useful in replacing traditional thread seaming in applications such as yoga apparel, swimwear, bodywear, outdoor apparel, and intimate apparel, to name a few. Heat sealing tapes can form a strong bond on garments and replace traditional stitching while providing excellent seam performance with high stretch and recovery. Heat sealing tapes can be calendared and extruded to the desired thickness and cut to the desired width, and may or may not be accompanied by a release liner made of PET, paper, coated paper, or other materials.

[0052] Some garments can be fully or partially assembled using a heat sealing process called continuous bonding. In a continuous bonding operation, the edges of the fabric can be cut or trimmed while the adhesive is being applied and cooled.

[0053] Continuous bonding machines reduce labor costs and speed up the process of making seamless garments. Seamless (sew free) seams can use elastic adhesive tapes such as polyurethane, PEBA (polyether block amide) and styrene block copolymers, which can be activated and bonded into the fabric by heat and pressure.

[0054] There are many types of continuous bonding machines used in the apparel market. The most common design consists of two silicone wheels with adjustable speed and pressure, as well as independent temperature control by hot air. A heated nozzle set blows hot air directly onto the belt, which softens or melts it by convection.

[0055] Heated air from air nozzles transfers heat through the surface area of ​​the elastic adhesive film. The adhesive tape is automatically fed into a continuous bonding unit and laid onto the fabric by side trimmers or folded over for hemming and binding.

[0056] Figure 1 An exemplary automatic continuous bonding system 100 is shown, which includes two wheels (rollers) 105, 110, which can control the speed and tension of the bonding operation, wherein one roller 105 can be used to operate the adhesive tape 115, and the other roller 110 can be used to operate the material such as fabric 120. Rollers 105, 110 can rotate clockwise and counterclockwise, respectively, and cooperate with heated air nozzles 125 to produce a final continuous bonding product 130. Using wheels 105, 110, the speed and tension of the bonding operation can be controlled. In some cases, the final product 130 can also be sold as a slit roll.

[0057] Applying the adhesive tape 115 requires two steps: a first laying operation, in which the adhesive has some initial tack to the fabric 120 for bonding, and a second operation, which may be on the hem of the leg opening, etc. The laying operation is usually performed on a continuous bonding machine, while the second operation may be performed on a continuous bonding machine or a heated flat press or other equipment.

[0058] It is critical to select the appropriate adhesive tape 115 to be used for continuous bonding. The adhesive tape 115 needs to have a sufficient glue line temperature (GLT) to soften or melt with the use of heated air and achieve a good bond with the fabric 120 in a short time while being released from the paper or PET carrier. The line can be operated at a speed ranging from about 1 meter / minute to about 4 meters / minute. In a manufacturing garment factory where speed and high production volume are critical, speed input becomes critical.

[0059] The heated air ejected from the air nozzle 125 is generally insufficient to soften / melt the SEBS block copolymer. The material blend embodiments of the present invention have improved adhesive properties that enhance their use in continuous bonding processes.

[0060] In one embodiment, the material blend includes a blend of styrene-ethylene-butylene-styrene (SEBS) block copolymer and an aromatic polyester polyurethane adhesive (ranging from about 5 wt % to about 10 wt %). In this embodiment, the TPU adhesive may be added by melt mixing during cast extrusion.

[0061] In some embodiments, the primary polymer is comprised of a soft rubbery styrene block copolymer having a hardness ranging between about 25 Shore A and about 50 Shore A and a melting point ranging between about 150°C and about 170°C.

[0062] In one embodiment, the adhesive blend comprises a plasticizer-free aromatic polyester-based polyurethane hot melt adhesive grade having a hardness range of about 50 Shore A to about 70 Shore A and a melting point range of about 100° C. to about 130° C. In some embodiments, the weight percentage of the adhesive blend in the primary polymer may be between about 5 wt % and about 10 wt %. In other embodiments, the material blend may exhibit the following mechanical properties: an elongation at break ranging from about 600% to about 900%, a tensile strength ranging from about 6 to about 9 MPa, a specific gravity of SEBS ranging from about 0.8 to about 0.9 g / cc, and a specific gravity of the blend of about 0.9 g / cc.

[0063] In some embodiments, the material blend may include a SEBS block copolymer mixed with a polyurethane, including a crystalline TPU. In other embodiments, the use of higher TPU loadings (equal to or greater than about 10%) may affect the inherent properties of the SEBS adhesive, such as stretchability and its subsequent recovery.

[0064] In some embodiments, advantages of the disclosed embodiments include, but are not limited to: low tape glue line temperature (GLT), high stretch, the tape can be applied to curved areas using continuous bonding by a machine that works only with heated air from a nozzle.

[0065] Therefore, the wider application range of the blend material can be considered to include the manufacture of three-dimensional (3D) cups, curved seams (such as leg openings), etc.

[0066] Additionally, the disclosed embodiments may also provide flexibility for customizing existing SEBS tapes to improve bonding to a wider variety of fabrics.

[0067] exist Figure 2 , Table 200 summarizes the results of a curved continuous bonding process using various combinations of resins and additives disclosed herein.

[0068] In summary, the present invention is a new adhesive material comprising a blend of SEBS and TPU. Current technology uses TPU based materials which are applied to garments by a continuous bonding process. The presence of SEBS in the adhesive enhances properties such as weatherability, stretchability and recovery. The addition of polar functional groups (such as OH, COOH, NH2, etc.) can improve the wettability of the adhesive material to the substrate. The presence of TPU (up to 20%) can enhance other properties such as recovery and stretchability of the SEBS / TPU blend.

[0069] One goal is to reduce the bond line temperature (activation temperature of the adhesive) of SEBS by adding TPU. Due to the increased surface energy, the blend can improve the wettability of SEBS on the substrate, while at the same time the small amount of TPU does not impair the functionality of SEBS.

[0070] Although only a few embodiments have been described in detail above, other modifications may be made. All such modifications are intended to be covered by the following claims.

Claims

1. An adhesive material composition comprising: Styrene-ethylene-butylene-styrene (SEBS) block copolymers are blended with 5 to 20 weight percent of an aromatic polyester thermoplastic polyurethane (TPU).

2. The adhesive material composition according to claim 1, wherein The styrene-ethylene-butylene-styrene block copolymer: Hardness range between 25 Shore A and 50 Shore A; and The melting point ranges between 150°C and 170°C.

3. The adhesive material composition of claim 1, further comprising an aromatic polyester-based polyurethane hot melt adhesive grade without plasticizer having a hardness ranging from 50 Shore A to 70 Shore A.

4. The adhesive material composition according to claim 1, wherein The plasticizer-free aromatic polyester based polyurethane hot melt adhesive grades have a melting point range of 100°C to 130°C.

5. Automatic continuous bonding system, comprising: a first roller for controlling the speed and tension of an adhesive tape comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer blended with 5 to 20 weight percent of an aromatic polyester thermoplastic polyurethane (TPU); a second roller, used to control the speed and tension of the fabric; and A heated air nozzle generates heated air to melt the adhesive tape onto the fabric passing between the first and second rollers.

6. The automatic continuous bonding system according to claim 5, wherein: The styrene-ethylene-butylene-styrene block copolymer: Hardness range between 25 Shore A and 50 Shore A; and The melting point ranges from 150°C to 170°C.

7. The automatic continuous bonding system according to claim 5, wherein: The adhesive tape further includes an aromatic polyester based polyurethane hot melt adhesive grade containing no plasticizer and having a hardness ranging from 50 Shore A to 70 Shore A.

8. The automatic continuous bonding system according to claim 7, wherein: The plasticizer-free aromatic polyester based polyurethane hot melt adhesive grades have a melting point range of 100°C to 130°C.

9. The automatic continuous bonding system according to claim 1, wherein: The plasticizer-free, aromatic polyester-based polyurethane hot melt adhesive grades allow for continuous bonding of three-dimensional geometries and seams with curved lines.

10. The automatic continuous bonding system according to claim 9, wherein: Adhesive blend grades containing plasticizer-free aromatic polyester-based polyurethane and styrene-ethylene-styrene block copolymers allow continuous bonding of three-dimensional geometries and seams with curves.

11. The automatic continuous bonding system according to claim 9, wherein: The plasticizer-free aromatic polyester-based polyurethane hot melt adhesive grade achieves continuous bonding at a bond line temperature below 137°C and an activation temperature below 150°C.

12. An adhesive material composition comprising: Styrene-ethylene-butylene-styrene (SEBS) block copolymers are blended with 5 to 20 weight percent of an aromatic polyether thermoplastic polyurethane.

13. The adhesive material composition according to claim 12, wherein: The styrene-ethylene-butylene-styrene block copolymer: Hardness range between 25 Shore A and 50 Shore A; and The melting point ranges from 150°C to 170°C.

14. An automatic continuous bonding system comprising: a first roller for controlling the speed and tension of an adhesive tape comprising a styrene-ethylene-butylene-styrene (SEBS) block copolymer blended with 5 to 20 weight percent of an aromatic polyether thermoplastic polyurethane (TPU); a second roller, used to control the speed and tension of the fabric; and A heated air nozzle generates heated air to melt the adhesive tape onto the fabric passing between the first and second rollers.

15. The automatic continuous bonding system of claim 14, wherein: The styrene-ethylene-butylene-styrene block copolymer: Hardness range between 25 Shore A and 50 Shore A; and The melting point ranges between 150°C and 170°C.

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