Umbrella fabric and umbrellas made from the same fabric

Abstract

To provide umbrella fabric and umbrellas using the fabric, which have a joining structure that prevents the occurrence of pinholes caused by sewing and ensures tensile strength and flexibility equal to or greater than that of conventional fabrics. [Solution] In a substantially polygonal umbrella fabric (1) for Western-style umbrellas, which is made up of multiple triangular sections (2) joined together, the joining is performed by folding the edges (2E) of adjacent triangular sections inward and overlapping them, and the overlapping sections (5) are bonded together via an adhesive layer (4) made of acrylic adhesive.

Description

Technical Field

[0006] , ,

[0001] This invention relates to a fabric for umbrellas and an umbrella using the fabric, in which no sewing seams occur when a plurality of triangular sections are joined. More specifically, it relates to a fabric for umbrellas and an umbrella using the fabric, in which the light-shielding property, waterproof property, and durability are improved by a specific adhesion structure.

Background Art

[0002] In recent years, umbrellas are not only sold as rain umbrellas, but also as umbrellas that can be used as sun umbrellas in situations where people have to go out, such as commuting or going to school, even in the sweltering heat of midsummer. They have become popular not only among women but also among men.

[0003] Umbrellas that can be used as both rain umbrellas and sun umbrellas are generally composed of laminating a light-shielding fabric on the back of the umbrella fabric for rain umbrellas (see, for example, Patent Documents 1 and 2). In this case as well, the manufacturing process of the umbrella fabric itself is common.

[0004] The basic manufacturing process is to cut the base fabric in the form of a piece goods to the product size, fold the both end sides that become the heli (edge) of the umbrella thinly inward in two steps, sew them from above with a dedicated sewing machine, and finish the ends. Then, in order not to cause loss in the fabric, it is cut into alternate triangular koma (sections). [[ID=H22]]

[0005] [[ID=H24]] \ For the sewing at this time, ridge portions where the edges of the sections overlap and protrude inward are used, and they are sewn manually at multiple locations along the parent ribs that are rotatably connected to the tip end portion of the middle rod of the umbrella rib and extend radially.

[0006] Furthermore, the seams on the equal sides of the panels are curved slightly outward, and by sewing adjacent panels together along this curve, the finished umbrella fabric can be fitted and attached to the curved ribs of the umbrella frame. As a result, the finished product becomes an umbrella with a slightly dome-shaped, roughly polygonal pyramidal shape.

[0007] Furthermore, when providing light-blocking and heat-shielding effects for use as a parasol, a light-blocking and heat-shielding sheet is laminated to the back of the fabric while it is still in its initial roll form, and then each triangular section is cut out. Therefore, the triangular sections, which already have the light-blocking and heat-shielding sheet attached to the back, are sewn together in the same way as a regular rain umbrella. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2011-56072 [Patent Document 2] Utility Model Registration No. 3176928 Gazette [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, with conventionally sewn umbrella fabrics, when the fabric is unfolded and used as an umbrella, strong tension acts on the entire fabric. As a result, the needle holes and the area around the stitching at the seams can be physically stretched, sometimes creating tiny pinholes.

[0010] Such pinholes allow sunlight to pass through to the inside when used as a parasol, reducing its light-blocking and heat-shielding effects. In particular, with the high-performance fabrics that have become mainstream in recent years, which have a black resin sheet with excellent heat-shielding and light-blocking properties laminated to the underside, the light leaking through the pinholes is easily noticeable as bright spots against the dark color of the inside, significantly reducing the sense of quality and the reliability of the light-blocking performance.

[0011] Furthermore, when used as an umbrella, surface tension initially prevents water from seeping through these pinholes, making them unnoticeable. However, with prolonged use, repeated opening and closing, as well as wind pressure from use in strong winds, can irreversibly enlarge these pinholes. In such enlarged pinholes, rainwater can seep through to the underside due to capillary action, potentially impairing the umbrella's function as a rain umbrella.

[0012] In view of the above-mentioned problems, the objective of this invention is to provide an umbrella fabric and an umbrella using this fabric that, by using a triangular joint structure that does not rely on sewing, prevents the occurrence of pinholes when the umbrella is unfolded, while ensuring tensile strength equal to or greater than that of conventional sewn structures, as well as the flexibility necessary for opening, closing, and folding operations. [Means for solving the problem]

[0013] To achieve the above objective, the umbrella fabric according to the invention described in claim 1 is an umbrella fabric with a substantially polygonal shape formed by joining a plurality of triangular sections, as shown in Figures 1 to 3. The aforementioned joining is characterized in that the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive.

[0014] According to the umbrella fabric described in claim 1 of this invention, the triangular sections are joined together by adhesion via an adhesive layer of acrylic adhesive, rather than by sewing. Therefore, even when tension is applied to the fabric when the umbrella is unfolded, there are no seams that would form pinholes. This completely prevents sunlight leakage, which is a problem with parasols, and also prevents raindrops from seeping in through pinholes. As a result, using this umbrella fabric provides an umbrella with improved light-blocking, waterproofing, and durability.

[0015] The inventor of this invention investigated various adhesives that could achieve strength equivalent to or greater than that of sewing by bonding, rather than by sewing, for joining umbrella fabrics, and concluded that a two-part acrylic adhesive was particularly suitable.

[0016] Commonly available two-part acrylic adhesives are widely used for DIY projects, making and repairing acrylic accessories as a hobby, due to their high transparency, weather resistance (resistance to yellowing), and excellent adhesion to plastics.

[0017] Acrylic adhesives come in two types: solvent-based and two-part. Two-part adhesives harden and bond through a chemical reaction that occurs when two liquids, a "main component" and a "hardener," are mixed. They harden rapidly at room temperature, reach practical strength in a short time, and are strong enough to be used as structural adhesives, possessing excellent toughness (impact and vibration resistance).

[0018] The excellent adhesive properties of such two-component acrylic adhesives stem from their dissolution-type bonding mechanism, which involves dissolving the resins together to create the bond. Therefore, strong adhesion is possible between synthetic resin sheets that can be surface-welded using the acrylic adhesive used. The inventor noticed that resin fabrics such as polyester and nylon, which are widely used as the fabric for ordinary umbrellas, could be applied to this invention, and thus arrived at this invention.

[0019] As described later in the embodiment of this invention, the adhesive strength between the edges of the triangular segments constituting the umbrella fabric was equal to or greater than that of conventional sewing. Furthermore, the overlapping portion of the bonded edges of the triangular segments ensures flexibility that does not hinder the opening and closing operation of the umbrella.

[0020] The umbrella fabric according to the invention described in claim 2 is characterized in that the adhesive width of the overlapping portion is in the range of 3 mm to 7 mm, as shown in Figure 2.

[0021] According to the fabric for umbrellas described in claim 2 of the present invention, by setting the width of the overlapping part between the small triangular spaces adhered with an acrylic adhesive within a specific range, good workability in the manufacturing process and sufficient bonding strength can be obtained simultaneously.

[0022] The sufficient adhesive strength within the range of 3 mm or more and 7 mm or less of this adhesive width has been actually confirmed by a tensile strength test as shown in the embodiments described later. If there is an adhesive width of at least 3 mm, sufficient joining (adhesive) strength can be obtained.

[0023] In fact, the overlapping width by conventional sewing is generally about 5 mm, and a width necessary for the sewing operation is ensured to a certain extent. However, in the present invention, when overlapping and adhering, a width smaller than that of sewing is possible. However, if the width is smaller than 3 mm, the operation itself of adhesion becomes difficult.

[0024] Of course, the wider the adhesive width, the greater the adhesive strength of the joint part as the fabric for umbrellas. However, since the adhesive area using the acrylic adhesive becomes larger, it becomes inefficient in both the amount of adhesive and the labor. Moreover, since this overlapping part becomes a ridge part on the back side of the umbrella, it becomes an obstacle in the use of the umbrella. Therefore, in the present invention, it is also preferable to set the upper limit to 7 mm, which corresponds to the upper limit of the width of the overlapping part in the case of general sewing joint.

[0025] The fabric for umbrellas according to the invention described in claim 3 is characterized in that, as shown in FIGS. 1 and 2, a heat insulating and light shielding sheet is laminated on each back surface in advance in the small triangular spaces by laminating.

[0026] According to the fabric for umbrellas described in claim 3 of the present invention, by laminating a heat insulating and light shielding sheet on the back surface of each small triangular space before joining, when used as an umbrella, it is possible to completely block the sunlight without any pinholes and to be an excellent sun umbrella that can also block heat well.

[0027] Furthermore, in this invention, the back surface of the triangular compartments that form the inside of the umbrella fabric does not affect the adhesion of the edges on the front side, thus allowing for greater flexibility in the materials used for lamination.

[0028] The umbrella fabric according to the invention described in claim 4 is characterized in that, as shown in Figure 2, the surface of the umbrella fabric is treated with a water-repellent coating using a fluorine-based or non-fluorine-based water-repellent agent.

[0029] According to the umbrella fabric described in claim 4 of the present invention, the surface is treated with a water-repellent agent, thereby improving the functionality of the umbrella fabric as a rain umbrella. The type of water-repellent agent used in the present invention is not particularly limited and may be any that has been conventionally used for water-repellent treatment of rain umbrellas. However, in the present invention, the joining of the edges of the triangular segments is done by interposing an adhesive layer made of acrylic adhesive. Therefore, depending on the adhesive properties of the acrylic adhesive used, it is appropriate to either apply a water-repellent treatment to the surface of the triangular segments before joining, or apply a water-repellent treatment to the surface of the fabric after it has been joined to become an umbrella fabric, so that the water-repellent agent does not affect the bonding of the edges of the triangular segments.

[0030] For example, when using a fluorine-based water repellent, by applying a water-repellent treatment to the surface after the triangular sections are joined to form the umbrella fabric, it is possible to prevent the water repellent from interfering with the bonding interface and safely improve the functionality of the umbrella without hindering the adhesive strength of general acrylic adhesives. Fluorine-based water repellents are coating agents mainly composed of fluororesin that form a finely fuzzy film on the fabric surface. This fuzzy texture lowers the surface tension, causing water droplets to bead up and roll off, and is commonly used in general umbrellas.

[0031] On the other hand, as a water repellent, in addition to those mainly composed of fluorine-based resins, non-fluorine-based water repellents with low environmental impact (for example, those mainly composed of silicone-based resins, paraffin-based waxes, acrylic-based resins, or urethane-based resins) can also be used. Therefore, when using non-fluorine-based water repellents that have relatively high affinity with acrylic adhesives, especially acrylic resins or paraffin-based waxes, a strong bond can be achieved with a general acrylic adhesive even if the triangular pieces are pre-treated with a water-repellent coating before joining, or even if this water repellent is present in the bonding area between the edges of the triangular pieces. In this case, the water-repellent treatment can be performed all at once on the fabric (roll) before the cutting and joining process, improving the efficiency of the manufacturing process. Furthermore, even when using materials that tend to inhibit adhesion, such as fluorine-based water repellents, it is possible to adopt a configuration in which pre-treated triangular pieces are joined together by selecting an acrylic adhesive that can handle difficult-to-bond materials.

[0032] The umbrella according to claim 5 is, as shown in Figure 3, an umbrella using the umbrella fabric according to the present invention, characterized in that the overlapping portion is sewn to the umbrella ribs.

[0033] By fixing the umbrella fabric according to the present invention to the umbrella frame, an umbrella can be obtained. However, since the umbrella fabric according to the present invention has an inwardly protruding overlapping section, just like conventional umbrellas, this overlapping section can be used to fix it to the same type of umbrella frame as conventional umbrellas, without the need to prepare a special, dedicated umbrella frame.

[0034] In this invention, the attachment of the overlapping sections to the umbrella ribs can be easily achieved by sewing each main rib along the corresponding overlapping section. In this case, since the edges of adjacent triangular sections are substantially integrated, the overlapping sections are easier to handle than conventional sewn overlapping sections where the ends are simply overlapped with open edges, and sewing them to the main ribs is easier. Therefore, the process of attaching the umbrella ribs becomes more efficient than before. [Effects of the Invention]

[0035] As described above, in the umbrella fabric according to this invention, the triangular sections are joined not by sewing, but by interposing an adhesive layer of acrylic adhesive to bond the overlapping parts. Therefore, when the umbrella is unfolded, the occurrence of pinholes caused by seams can be completely prevented, thereby enhancing the light-blocking performance as a parasol, preventing water seepage for extended periods as a rain umbrella, and achieving both tensile strength equivalent to or greater than conventional sewn structures and flexibility that does not hinder the opening and closing of the umbrella.

[0036] Furthermore, since the umbrella according to this invention can be constructed by simply sewing each main rib of the umbrella frame along an overlapping section that is substantially integrated via an adhesive layer, the sewing work is easier compared to conventional open overlapping sections, thereby improving the efficiency of the manufacturing process and stabilizing product quality. Moreover, since it does not require a special frame structure and can utilize existing umbrella frames of the same type as conventional ones, it also boasts excellent versatility. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram showing the structure of an umbrella fabric according to one embodiment of the present invention, where (a) is a plan view of the back side of the triangular segments that make up the umbrella fabric before joining, and (b) is a plan view of the front side of the umbrella fabric formed by joining all the triangular segments in (a). [Figure 2] Figure 1 is a schematic diagram showing the bonding state of adjacent edges between triangular sections, where (a) is a perspective view of the overlapping section and (b) is an enlarged end view of section A in (a). [Figure 3] Figures 1 and 2 are perspective views showing an umbrella constructed by sewing the umbrella fabric shown in Figures 1 and 2 onto the umbrella frame. (a) is a partial perspective view of the umbrella from the inside, showing the central part, and (b) is a partial perspective view of the umbrella from the inside, showing the edge. [Figure 4] This is a schematic diagram showing the state of a test specimen when a tensile strength test was performed on a partial sample of the overlapping portion of the umbrella fabric according to this embodiment. [Modes for carrying out the invention]

[0038] An embodiment of the present invention will be described below with reference to the drawings.

[0039] <Embodiment> The configuration of a parasol fabric 1 according to one embodiment of the present invention, which is provided with heat-shielding and light-blocking functions, will be explained with reference to Figures 1 and 2. In this embodiment, the parasol fabric 1 is formed by joining together, for example, six, eight, or more triangular sections 2 at the edges of adjacent isosceles triangles with their vertices as the center, to form a roughly polygonal, integrated parasol fabric 1.

[0040] Each triangular section 2 is made by laminating a heat-shielding and light-shielding resin sheet onto the back of a roll of fabric material, such as polyester, and then finishing the edges that will form the umbrella rim. Finally, it is cut into predetermined isosceles triangles in predetermined alternating patterns to avoid any fabric waste.

[0041] In this embodiment, the triangular sections 2 are joined together by bonding adjacent equal-sided edges 2E that are folded inward (back side) via an adhesive layer 4 made of a two-part acrylic adhesive, as shown in Figure 2. By performing this bonding for all the triangular sections 2, a roughly polygonal umbrella fabric 1 is obtained as shown in Figure 1(b).

[0042] As described above, the umbrella fabric 1 has an inward-facing protrusion formed as an overlapping section 5 where the edges 2E of the bonded triangular sections 2 overlap.

[0043] In reality, since the vertices of all the triangular sections 2 are not glued, as shown in the plan view of Figure 2, the roughly polygonal umbrella fabric 1 after joining forms an opening 6 in the center. This opening 6 functions as a through hole for the tip (ferrule side) of the central shaft 20 to pass through from the inside to the outside of the umbrella when the umbrella fabric 1 is fixed to the umbrella ribs 11 to complete the umbrella 10.

[0044] The bonding strength of the overlapping section 5 of the umbrella fabric 1 according to this embodiment must be at least as strong as or greater than the bonding strength of the sewn section of a conventional umbrella fabric. Therefore, the bonding strength of each overlapping section 5 with a different adhesive width W according to this embodiment was verified below using a tensile test (JIS L 1093 A-1 method) to measure the strength of a sewn seam.

[0045] For this tensile test, three types of test specimens 100 were provided, each having a joint 105 corresponding to the overlapping portion 5 in this embodiment, with adhesive widths W of 3-4 mm, 6 mm, and 7 mm. As shown in Figure 4, five specimens were taken from each test specimen 100, cut horizontally (laterally) 100 mm and vertically (vertically) 150 mm or more, centered on the joint (overlapping portion) 105.

[0046] For specific bonding methods, when the bonding width W is narrow (3-4 mm), the pre-mixed acrylic adhesive is applied in a single line (bead-like) along its length to one edge 2E, and the other edge 2E is overlapped and pressure is applied to uniformly spread the adhesive across the entire width of the edge 2E. After that, it is held in place with clamps for several minutes to 10 minutes to allow it to cure.

[0047] Furthermore, in the case of relatively wide bonding widths W of 6 mm and 7 mm, the same process was used: two bead-shaped strips of pre-mixed acrylic adhesive were applied to one edge 2E along its length, the other edge 2E was overlapped and pressed, and the adhesive was spread uniformly across the entire width of the edge 2E.

[0048] Afterward, the clamped state was maintained for several minutes to 10 minutes to allow it to cure. In other words, when the bonding width W is 6 mm or 7 mm, the amount of adhesive used is essentially double that when the bonding width W is 3 to 4 mm.

[0049] In the tensile testing machine, two pairs of front grips 110 (25mm x 25mm) and back grips 120 (25mm x 51mm) were set up vertically, with a gripping distance D of 76mm.

[0050] Then, for each test specimen 100, both the upper and lower sides were clamped between the pairs of front and back grips (110, 120), and the tensile testing machine was driven with the lower front and back grips fixed, while the upper front and back grips were raised and pulled at a speed of 300 mm / min.

[0051] The results of each tensile test are shown in Table 1 as the average tensile strength (N) at the point when the joint 105 of the test specimen 100 first fractured. For comparison, the standard seam strength value of 145N or higher for typical umbrellas is also shown here. In other words, a typical umbrella is required not to experience "seam breakage," "fabric tearing," or "significant seam opening" when subjected to a load of 145N.

[0052] [Table 1]

[0053] As is clear from the results in Table 1, the tensile strength of the joint in the overlapping section 5 of the umbrella fabric 1 according to this embodiment is far greater than the tensile strength criteria value for conventional sewing, and it was found to be sufficiently suitable for practical use.

[0054] Furthermore, in the case of existing umbrella products, high-quality umbrellas with a solid construction often use strong fabrics and threads, resulting in a tensile strength at seam breakage of around 300N or more, which is significantly higher than the standard value.

[0055] The umbrella fabric 1 according to this embodiment ensures strength equivalent to or greater than that of high-quality, high-strength sewn umbrella fabrics, even with a relatively small bonding width W of 3 to 4 mm. Furthermore, since the improvement in tensile strength becomes gradual even when the bonding width W is increased, it has been confirmed that the range of 3 mm to 7 mm is extremely suitable for balancing flexibility and strength.

[0056] As shown in Figure 3, the umbrella fabric 1 according to the above embodiment was sewn and fixed to the umbrella ribs 11 to complete the umbrella 10. Here, a two-stage folding umbrella is shown as an example. The sewing thread used was a relatively thick (30 to 50 count) polyester thread, which has excellent strength and elasticity and is widely used in conventional umbrellas, and the sewing was basically done in the same way as before.

[0057] The umbrella frame 11 is the same type as that used for conventional two-stage folding umbrellas. Specifically, the umbrella frame 11 mainly consists of a predetermined number of main ribs 12 that are rotatably connected to the upper part of the central shaft 20 and extend radially, support ribs 14 that transmit rotational movement for opening and closing from a lower ferrule 21 that slides vertically along the central shaft 20 to the main ribs 12, and a tip rib 15 for folding each main rib 12 in the middle.

[0058] The fabric 1 for the umbrella is sewn in place at several points along each rib 12, at the overlapping portions 5 of the edges 2E of adjacent triangular sections 2 that are bonded to each other via an adhesive layer 4. In this embodiment, the overlapping portions 5 are sewn to the ribs 12 at three sewing points (S1, S2, S3) at the tip 15, the tip of the rib 16, and intermediate positions between them.

[0059] As described above, when the umbrella 10, which is completed by sewing the umbrella fabric 1 to the umbrella frame 11, is unfolded and high tension is applied to the umbrella fabric 1, there are no needle holes at the joints, so the occurrence of pinholes that cause light leakage and water ingress is completely eliminated.

[0060] Furthermore, the sewing points (S1, S2, S3) of the umbrella fabric 1 to the umbrella ribs 11 utilize the overlapping parts 5 that are formed as protruding parts on the inside of the umbrella 10, so the seams do not affect the outside in any way.

[0061] Furthermore, in an opening and closing test of the umbrella 10 obtained in this embodiment, the opening and closing operation was repeated 500 times. No damage or malfunctions in opening and closing occurred, confirming that a high-quality umbrella 10 product was obtained.

[0062] Furthermore, by applying a water-repellent coating layer 7 of a fluorine-based water-repellent agent to the surface of the umbrella fabric 1 obtained by joining the polyester triangular sections 2, the waterproofness of this umbrella 10 as a rain umbrella can be enhanced.

[0063] In the embodiments described above, a two-stage folding umbrella was used as an example, but the umbrella fabric 1 according to the present invention is not limited to this. Needless to say, it can be applied to all types of umbrellas, such as long umbrellas (straight umbrellas), multi-stage folding umbrellas with three or more stages, or automatic opening and closing umbrellas, depending on the specifications and structure of the umbrella ribs 11 used.

[0064] Furthermore, regarding two-component acrylic adhesives, new products have been developed in recent years that can bond resin materials together with sufficient strength even when a fluorine-based water repellent, mainly composed of fluororesin, is interposed. Therefore, when using such new two-component acrylic adhesives, it is also possible to apply a water-repellent treatment to the surface of each triangular compartment 2 with a fluorine-based water repellent beforehand, and then bond their edges 2E together.

[0065] Furthermore, when using a non-fluorine-based water repellent that exhibits high adhesion even with general acrylic adhesives, it is possible to pre-treat the surface of the triangular box 2 with such a non-fluorine-based water repellent before joining. [Explanation of Symbols]

[0066] 1: Fabric for western umbrellas 2: Triangular booth 2E:Edge 3: Light-blocking and heat-shielding sheet 4: Adhesive layer 5: Overlapping parts W: Adhesive width 6:Aperture 7: Coating layer (fluorine-based water repellent) 10:Western umbrella 11: Umbrella bone 12: Main bone 14:Bone 15: First 16: Dew point S1, S2, S3: Sewing locations 20: Central pole 21: Lower potter's wheel 100: Test piece 105: Joint 110: Front side grip 120: Grab from the back D: Grasp interval

Claims

1. In a roughly polygonal umbrella fabric for Western-style umbrellas, which is formed by joining together multiple triangular sections, The aforementioned joint is characterized in that the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive.

2. In a roughly polygonal umbrella fabric for Western-style umbrellas, which is formed by joining together multiple triangular sections, The aforementioned joint is formed when the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive. A fabric for umbrellas characterized in that the adhesive width of the overlapping portion is within the range of 3 mm to 7 mm.

3. In a roughly polygonal umbrella fabric for Western-style umbrellas, which is formed by joining together multiple triangular sections, The aforementioned joint is formed when the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive. The aforementioned triangular compartments are characterized in that heat-shielding and light-shielding sheets are laminated onto the back surface of each compartment in advance.

4. In a roughly polygonal umbrella fabric for Western-style umbrellas, which is formed by joining together multiple triangular sections, The aforementioned joint is formed when the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive. A fabric for umbrellas characterized by having its entire surface treated with a water-repellent agent, either fluorine-based or non-fluorine-based.

5. An umbrella made of umbrella fabric with a roughly polygonal shape formed by joining together multiple triangular sections, The aforementioned joint is formed when the edges of adjacent triangular sections are folded inward and overlapped, and the overlapping portions are bonded together via an adhesive layer made of acrylic adhesive. The adhesive width of the overlapping portion is within the range of 3 mm to 7 mm. An umbrella characterized in that the overlapping portion is sewn to the umbrella ribs.

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