KR20090113277A - Fastener web with microstructured particles - Google Patents

Abstract

Hook fasteners are disclosed that can be engaged with a suitable loop fabric. The hook fastener includes a base substrate 70 having a surface having a plurality of fastening protrusions 72, wherein the fastening protrusions are attached to the top surface 73 and to the surface of the base substrate at the joint connection 75. With 74, the top surface of at least some of the fastening protrusions include nonlinear microstructured features, such as intersecting peak and / or valley structures 77.

Hook fasteners, loops, peaks, valleys, fastening protrusions, microstructured

Description

FASTENER WEBS WITH MICROSTRUCTURED PARTICLES}

The present invention relates to the manufacture of male components for fasteners, in particular touch-and-close type fasteners, also known as fasteners of hook-and-loop type. It is about a method.

Hook-and-loop type mechanical fasteners for limited applications such as fixing disposable diapers typically use shaped types of hooks.

One approach is the direct molded hook disclosed in US Pat. No. 5,315,740, for example, assigned to Velcro, in which the molded hook displaces only a small volume of loop fabric for engagement with the loop fabric. Disclosed is a shaped hook having a small displacement volume so as to only require it. This patent discloses a re-entrant hook, ie a hook whose tip portion is bent down thereon from the top of the hook toward the base sheet such that the tip portion forms a fiber retention recess on the bottom of the hook.

It is also known to cap the shaped stem onto the web. Mushroom-shaped fastening protrusions obtained by this process are disclosed in US Pat. No. 5,679,302 and US Pat. No. 5,879,604, wherein the extruded polymer layer is pressed against a mold having a mold cavity, the cavity being integral with the base. To form an overhanging stem. The distal end of the stem is then deformed by a heated pressure roller to form a loop fastening protrusion. U. S. Patent No. 6,054, 091 discloses a similar method, wherein a heated deformation surface provides essentially lateral deformation to the stem during deformation, forming a concave J-shaped hook with a flat upper portion. The solution of US Pat. No. 6,627,133 differs from the previous one in that the stemmed web capped by the heated pressure roller is manufactured by the method of US Pat. No. 6,287,665, ie by a special mold constructed by a cylindrical printing screen. . All documents mentioned in this paragraph are similar in that they flatten the preformed stem by hot rolls.

US patent application 2004 / 0031130A1 discloses a method in which an article comprising a stem integral with and protruding from the polymer base and the base is extruded by a mold roll having a plurality of sophisticated mold cavities. The distal ends of the stems are then heated and melted, but their feet remain low temperature solids. The molten end is then flattened by the deformation surface. The same approach, preheating and subsequently flattening the stem, is disclosed in US Pat. No. 6,592,800, US Pat. No. 6,248,276 and US Pat. No. 6,708,378, the latter approach capping the rough contact surface to rough the fastening protrusion. It also discloses creating a true flat top.

Although particles have also been proposed to produce hook fasteners, none are known to be commercialized. U. S. Patent No. 3,550, 837 discloses a male fastener member composed of irregularly shaped granules having a special polyhedral surface, each fastening protrusion being glued to the base. The fasteners are suitable for securing the flaps of a disposable carton unopened. The fastening is provided by granules comprising a number of small flat planes that form a polyhedral surface.

In U. S. Patent No. 3,922, 455, nibs of various shapes are incorporated onto the linear filaments, and the linear filaments projecting from the base form fastening elements of the male fastener component.

In WO 01/33989, particles are randomly scattered and fixed on a base by a scatter head of a scatter coater. Each fastening protrusion is composed of several aggregated particles, but some individual particles may also be left.

It is an object of the present invention to provide a low cost male mechanical fastener with advantageous properties. It is another object of the present invention to provide commercially attractive alternatives to the mechanical male fastener systems used so far and their manufacturing methods.

Summary of the Invention

The present invention provides a hook fastener that can be engaged with a suitable loop fabric and a method of forming such a hook fastener, the hook fastener comprising a base substrate having a surface having a plurality of fastening protrusions. A fastening protrusion having an upper surface, and an attachment end coupled to the surface of the base substrate at the joint connection, wherein an upper surface of at least some of the fastening protrusions has an intersecting peak and / or valley structure. Is formed. In one embodiment, at least some of the peak structures are discrete structures surrounded by valley structures, wherein at least some of the discrete peak structures are in contact with the material of the upper surface at different heights. Alternatively, at least some of the valley structures may be discrete valley structures surrounded by peak structures. In general, at least some of the peak structures and / or valley structures intersect at one or more locations. In various embodiments, the height of the top surface structure can be at least about 20 micrometers, alternatively at least about 50 micrometers. In various embodiments, at least some of the upper surfaces of the fastening protrusions have at least one edge with a mantle surface that forms an angle of at least about 20 degrees, alternatively at least about 30 degrees.

The present invention also provides a hook fastener capable of engaging with a suitable loop fabric and a method of forming such a hook fastener, the hook fastener comprising a base having a front surface and a rear surface, wherein at least one surface is an upper surface And a plurality of fastening protrusions having attachment ends secured to the surface of the base at the joint connection, wherein an upper surface of at least some of the fastening protrusions comprises non-linear microstructured features and includes non-linear microstructured features. The fastening protrusions have an average height to diameter aspect ratio of at least about 0.7. In various embodiments, the height of the upper surface structure can be at least about 20 micrometers, alternatively at least about 50 micrometers.

The invention also provides a first method for forming a fastener as described above, which method comprises:

Providing a plurality of suitable polymer particles;

Providing a base having a front surface;

Dispersing a plurality of polymer particles into at least one discrete area of the contact release surface onto the microstructured contact release surface, wherein the microstructured contact surface comprises a plurality of intersecting peaks and / or Or has a nonlinear surface microstructure, such as a valley structure;

Providing polymer particles dispersed on the contact release surface in a semi-liquid state of suitable viscosity, wherein at least some of the particles in discrete regions or areas are subjected to a preform projection having an edge angle of at least 30 degrees. Contact with the contact release surface for a time sufficient to deform;

Guiding and securing the anterior surface of the base to the distal end of at least some of the preform protrusions;

Removing the base from the contact release surface to separate the preform protrusions secured to the contact release surface;

Thereby forming a fastening protrusion that projects from the front surface of the base.

Polymer particles are generally dispersed within the microstructured contact release surface. The polymer particles may impinge on the structured contact release surface by gravity, electrostatic attraction, impact or other suitable force, or any combination thereof. In a preferred method, the polymer particles are dispersed on the contact release surface using electrostatic attraction that impinges the particles on the contact release surface.

1 is a schematic side view of an apparatus for manufacturing the fastener of the present invention.

2 is a cross-sectional view of the base substrate with fastening protrusions.

FIG. 3 is a 200 times SEM plan view of a contact release surface with pyramidal microstructures. FIG.

4A is a 40 times SEM side view of the base film with fastening protrusions with microstructured top surface.

FIG. 4B is a 100 times SEM side view of the base film with fastening protrusions having a microstructured top surface. FIG.

5 is a cross-sectional view showing an aspect ratio of a fastening protrusion.

6A-6C illustrate various microstructures that can be used on the contact release surface of the present invention.

7 is a SEM micrograph showing various microstructures that can be used on the contact release surface of the present invention.

The present invention provides a fastener that engages a loop fabric. 2, the fastener includes a base substrate 70 having a surface 71 with a plurality of fastening protrusions 72. The fastening protrusion has an upper surface 73, and the upper surface end of at least some of the fastening protrusion forms an edge 80 surrounding the protrusion. Opposite the upper surface 73 is an attachment end 74 attached to the front surface of the base at the junction connection 75. There may be a mantle surface 76 extending from the top surface edge 80 to the attachment end 74. In some embodiments, the mantle surface has at least one contour of the side view of the mantle surface strictly convex from the top surface edge to the attachment end. The upper surface 73 of at least some of the fastening protrusions has a nonlinear microstructure 77. The microstructures have a vertical dimension (height or depth) 81. Such nonlinear microstructures may include at least some intersecting peaks 78 and / or valleys 79.

The hook fastener may have a plurality of fastening protrusions that form discrete or continuous shapes. The shape is defined as a plurality of fastening protrusions organized within a specific area or area, and there are some or different types or sizes of fastening protrusions outside this area. The features need not have clearly defined edges, but rather can have a gradual change in the density or distribution of the fastening protrusions, for example, from the high density fastening protrusion area to the area of the adjacent low density fastening protrusions. This low density fastening protrusion area may have little or no hook fastening protrusions. Preferably, the feature is formed by a plurality of fastening protrusions in an area with fastening protrusions of relatively high density. The plurality of fastening protrusions forming the desired shape may extend substantially continuously to one dimension range of the base substrate. The feature may be surrounded by a second area having any of the fastening protrusions of different types and / or densities. The feature or fastener may have a relative average density of fastening protrusions of at least 1 gram per square meter (gsm) of particles having a coarse average size of approximately 50 to 1000 micrometers or generally of 50 to 500 micrometers or of at least 2 gsm of such particles. It can be formed into a high density region. (Note that the average size of the fastening protrusions and the density of the fastening protrusions material can be used to convert these measurements into the number of fastening protrusions per area). In another alternative, the second region or fastener may have a fastening protrusion average density that is less than about 50% of the fastening protrusion average density in the high density region as a whole, or less than about 25% of the fastening protrusion average density in the high density region. For such features that extend continuously into one dimension range of the base, the features will generally have a minimum width dimension that is less than the width of the base. The feature will generally have a minimum width dimension of greater than 1 mm or greater than 4 mm.

The fastening protrusions in the form of discrete features can be applied through a variety of methods, as described in detail in commonly pending application No. 11/530499, which is incorporated herein by reference.

As mentioned, the polymer particles used to form the fastening protrusions can be colored, tinted, colored, etc. for specific visual purposes. Fastening protrusions of different colors, or fastening protrusions of different density or size, may be provided in multiple areas for a particular visual effect.

The invention also includes the use of an adhesive, preferably a pressure sensitive adhesive (PSA). Such PSAs include a wide variety of materials known in the art, such as natural rubber adhesives, block copolymer based PSAs (e.g., based on elastomers available from Kraton Polymers, Houston, TX), Acrylate based PSA, and silicone based PSA. PSAs may be selected to bond well to polyolefin thermoplastic materials (eg, polypropylene, polyethylene, and copolymers and blends thereof), for example, the name LSE (eg, LSE 300) from 3M Company. It may include the PSA family available as. Other suitable compositions may be based on silicone-polyurea-based pressure sensitive adhesives. Such compositions are described, for example, in US Pat. No. 5,461,134 and US Pat. No. 6,007,914.

In one embodiment, the PSA may be provided at a predetermined area adjacent to the area having the fastening protrusions. Either or both of the PSA and fastening protrusion regions may be present as discrete or continuous regions.

The base used in the method of the present invention can be any suitable continuous or discontinuous base web such as porous or nonporous polymeric film, laminate film, nonwoven web, paper web, metal film and foil and the like. The base can be modified by any known method, such as by printing, embossing, flame treatment, laminating, particle coating, coloring, and the like. The polymer film used as the base may or may not be oriented. In connection with the method described below, the base film may be provided to have a varying area of ability to bond to the preform protrusions, which provides another substrate that provides a fastening protrusion area present in discrete features, patterns, or the like. That's the way. The base film surface can be smooth, or a protrusion formed in the base that can be used as a ripstop, tear propagation line, or other feature, which can be on the front or back side of the base. Or features such as valleys.

The surface of the base can also be roughened, for example by particles that have been previously scattered and fixed thereon. The particles must be introduced and fixed on the base in such a way that at least the distal end of the protrusion can be formed from the particles. The protrusions can be composed entirely of such particles without any further modification of the particles. In order to introduce and fix the particles to the (smooth or roughened) front surface, for example, in the cited international application publication WO 01133989, the entire disclosure of which is incorporated herein by reference, for example, such as random scattering and adhesion There are ways to teach.

As used herein, the word "particle" refers to solid, liquid or semi-liquid particles, including, for example, granules, pellets, powders and droplets. Appropriate particles can be selected based on the discussion herein. When embodiments of the invention (described below herein) are used that rely on electrostatic deposition of the particles, the particles should be selected to be compatible with this process. In electrostatic deposition, the particles are moved under the influence of an electric field to impinge on the base (either on a selected area or uniformly on the entire area of the base). Thus, in this case, the particles must be easy to charge them (otherwise they will not move under the influence of the electric field). Such methods are well known in the art and the selection of such particles is easy.

With regard to the properties of the fastening protrusions formed from the particles, it may be desirable if at least some of the fastening protrusions have a side appearance that is strictly taper from the top surface or top surface edge to the attachment end at the front surface of the base. As used herein, lateral appearance means an appearance taken perpendicular to the front surface of the base. Forward tapering means that the closer the engaging projection is to the base, the narrower the projection. For example, the cylinder is not a forward tapering shape. This type of tapering will pull the fastened fibers down to the front surface of the base without the trapped fibers being captured in the non-tapered portion displaced from the front surface of the base when a shear load is applied to the fastener. Thus, it may be possible for the base to be made weaker by minimizing the torque to the fastening protrusion, i.e. it may be cheaper, more flexible, more skin-friendly, thinner, and so on. In addition, the fasteners can have a relatively large surface area defined by the top of the protrusions to give the fasteners a smooth contact, and at the same time can also have a relatively small total surface area of the protrusion attachment ends connected to the base to provide flexibility and Increases skin affinity. The fastening protrusion can also be characterized by the ratio of the perimeter of the fastening top area to the height of the fastening protrusion, which is generally 1.1 to 50, preferably 1.2 to 20. The fastening protrusion also generally forms an overhanging rim, which is generally the difference between the top surface area and the attachment end area.

A preferred general group of methods for converting topics from materials used in the method of the invention to produce male fastener components of fastening protrusions in accordance with the invention is generally:

Providing a base having a front surface;

Providing particles of polymeric material;

Providing a molded release surface with a non-linear surface structure to provide a large surface tension suitable for stopping flow of at least semi-liquid or softened polymer particles;

Dispersing a plurality of polymer particles on the contact release surface;

The polymer particles are brought into or at least in a semi-liquid or softened state with a suitable viscosity, such that the preform protrusions are located on the release surface and protrude from the corresponding distal ends (the preform protrusions are at least to some extent the fastening end). Means a protrusion preformed in the shape of the final fastening protrusion). Along the edge thereof in contact with the contact release surface, the preform protrusions will form a contact angle, which is affected by the surface energy of the microstructures and polymer particles provided on the contact release surface. The polymer particles remain semi-liquid for a period of time suitable to form an acute contact angle of at least about 20 degrees relative to at least a portion of their edges in contact with the contact release surface;

The preform protrusions may then be at least partially solidified to contact and secure the distal end of at least some of the preform protrusions and the anterior surface of the base while maintaining the shape of the edge formed by the contact release surface essentially;

The preform protrusions are then further solidified sufficiently to separate and remove the preform protrusions from the contact release surface, forming a fastening protrusion attached to the base. These formed fastening protrusions protrude from the front surface of the base to the microstructured top, which was formed on the microstructured release contact surface. The structured top at least partially overhangs the base to form a rim, and is at least partially bounded by edges having an angle affected by the acute contact angle.

The microstructured contact release surface is designed to allow a wide range of semi-liquid or softened polymer particles to be used without the need to match the surface energy of the contact release surface closely to that of the polymer as discussed below.

Gravity can be used where the particles can simply fall onto the decontacting surface. Another way to introduce the particles onto the contact release surface is by electrostatic deposition. In this method, the polymer particles are directed towards the contact release surface by the electrostatic driving force. This is done by providing these two electrodes such that an electric field is formed between the two electrodes. The first electrode is located in front of the contact release surface. The second electrode is located behind the contact release surface. Voltage is applied to the electrodes to create an electric field between the electrodes. Upon introduction of suitable particles into the gap between the first and second electrodes, the particles are diverted and then driven in the direction of the second electrode under the influence of the electric field.

Electrostatic deposition is most advantageously performed in a vertical configuration in which the second electrode is positioned above the first electrode. In such an arrangement, the particles are driven upwards against gravity, so that particles that collide with but do not adhere to the contact release surface can fall back down to be collected and / or reused. This method has the advantage of providing a more uniform distribution of particles onto the contact release surface. All particles will be equally charged and repel each other. This will contribute to keeping the particles evenly distributed and preventing individual particles from forming a number of integrated preform protrusions. This method is advantageous for providing a uniform distribution of particles on the contact release surface.

Polymeric particles should be selected for compatibility with the electrostatic coating. The main requirement is that under the influence of an imparted electric field, the particle has a sufficient induced charge so that a sufficient force is applied to the particle to move the particle between the two electrodes by the electric field. Preferably, the electric force must overcome gravity so that the aforementioned vertical configuration can be used. Fortunately, most of the materials suitable for forming the preform protrusions (ie, thermoplastic powders such as polypropylene, etc.) are dielectric materials (i.e. can have charges induced upon placement in the electric field). Particles suitable for forming the preform protrusions are also generally small and low density (and therefore light in weight), making them easier to drive upwards against gravity through electrostatic forces.

The particles must be placed in the gap in any way such that they are driven towards the contact release surface under the influence of an electric field. Ideally this is done in a uniform manner. The particles are sprayed, dropped, blown, or otherwise injected into the gap by methods well known in the art. In the above vertical configuration, the particles can be injected laterally into the gap by spraying. Alternatively, the particles can be introduced into the gap by a carrier belt that enters the gap so that the particles move freely towards the contact release surface by the applied electric field in the presence of the particles on the top surface.

Other methods besides the electrostatic deposition and gravity assisted deposition described above are possible. Alternative methods for selectively introducing particles into the contact release surface include colliding the particles by forced airstream, mechanical projection or conveying, or the like.

In the case of fusion (ie, melt bonding), the bases of the different polymeric materials and the preform protrusions may not bond well with each other. Thus, for example, the placement of the preform protrusions of polystyrene onto the base film of polypropylene (or vice versa) may cause little or no bond formation. However, if a compatibilizing layer is placed on the polypropylene base film, improved bonding can be achieved. Such commercialization layers may be continuously or patterned by a wide variety of methods in the art, including pattern coating, screen printing, vapor coating, plasma coating, photolithography, chemical vapor deposition, or the like, in a discrete or discontinuous manner. Can be applied.

The compatibilization layer can include any well known tie layer and bonding layer available in the art. What is needed is that the commercial tie layer have sufficient adhesion to the base and sufficient adhesion to the polymer particles used to form the preform protrusions. In this approach, the polymer particles and base film may no longer need to be formed of exactly the same material, or very close or similar materials in composition. This allows the base and polymer particles to be selected based on the most desirable physical properties for each. For example, it may be desirable to select very soft and flexible base films and very hard and rigid polymer particles (or vice versa). The use of a compatibilizing layer on the base film allows this to be done.

When using a contact release surface that allows deposited particles to flow in one or more directions, it is necessary to appropriately select a polymer suitable for the particles and a contact release surface of suitable surface energy. Another consideration for the particles selected is that they have a suitable viscosity at the temperature of the contact release surface where they will wet the contact release surface within a suitable time. The surface energy of the contact release surface can be formed by known materials and methods such as siliconized surfaces, fluorine compounds, corona discharges, flames and the like. The contact release surface should be able to release the particular polymer particles that are used, semi-liquefied and solidified. Certain release surfaces are known to release certain polymers, but not other polymers. For example, a polyethylene release surface can release suitable polypropylene particles, but certain polyethylene particles tend to fuse or fuse with each other and do not release such particles. As used herein, the word "release" refers to the phenomenon that particles detach from the contact release surface without (unacceptable) damage or loss of the material of the particles or preform protrusions. However, in the method of the present invention, the release contact surface is selected to have a surface microstructure that does not allow the deposited particles to flow uninterrupted in a predetermined direction, rather the microstructures provide to stop polymer flow. A wider range, while reducing the problem of excessive wetting of the disengaging surface due to too much flow in a predetermined direction due to contact time and / or relative surface energy at a given temperature. The release energy can be used on the surface of the contact release surface.

Dispersing the particles on the contact release surface by gravity can be carried out in any suitable manner, for example by dispersing the particles by a scattering unit. Other methods are also mentioned herein. Particles should be dispersed at a predetermined rate per unit surface area so that they form preform protrusions, where one particle can form one preform protrusion. The particles may be at least semi-liquid before, during, and / or after dispersing the particles onto the off-contact surface. "At least semi-liquid" means liquid or semi-liquid. Suitable ways of liquefying will depend on the properties of the polymer selected and may include, for example, heating, thinning, dissolving, emulsifying, dispersing, and the like.

Solidity (a degree or extent of solidification) suitable for contacting and securing the preform protrusions on the contact release surface with the front surface of the base may be determined by one skilled in the art depending on the particular situation. That means, but not necessarily, that the preform protrusions are more solid than those formed on the contact release surface. Preferably, the preform protrusions should be solid enough to contact the front surface of the base while at least partially maintaining their shape. It usually usually means maintaining at least the minimum free height of the preform protrusions, and also a suitable edge angle. Setting the required solid form to the preform protrusions will be material dependent and may include cooling, drying, heating, crosslinking, curing, chemical treatment, and the like. A suitable solid formed preform protrusion, located on the contact release surface, may be covered by the base front surface such that the front surface of the base can be contacted and secured with the preform protrusion end. Fixing the distal end of the preform protrusion to the front surface of the base can be obtained by crosslinking by ultraviolet irradiation, for example by bonding with an added adhesive (eg, a pressure sensitive adhesive, a hot melt adhesive, or a UV curable adhesive). Or it may utilize inherent adhesion or fusion of the material in contact (base front surface or preform protrusion). When the preform protrusions are removed from the contact release surface they must be solid enough to at least partially maintain their shape during separation from the contact release surface. It usually means preserving a suitably strong bond with the front surface of the base, but mainly maintaining a suitable overall shape, especially for the edge angles formed. The base should generally be solid enough to maintain its shape and to separate the preform protrusions from the contact release surface. The top surface structure will most likely be determined by the contact release surface. However, post treatments, such as non-contact heat treatment, may be used that allow the top surface to be essentially flat or droop in. If a large number of small protrusions are advantageous, it may be desirable in the method that at least some of the individual preform protrusions comprise exactly one polymer particle per preform protrusion.

It may be desirable in the method that at least some of the preform protrusions are provided with a contact angle of about 20 ° to about 85 °, preferably about 30 ° to about 80 °. This will be in the range of contact angles for most of the individual preform protrusions. For preferred embodiments, this range will be the average contact angle for the preform protrusions.

In the method it is desirable if at least some fastening projections are provided with a profile which is tapered (preferably net convex) from the upper or upper edges of which the flattening projections are flattened (preferably net convex) of the base from their respective side appearances. have. This is usually very easy to achieve by this method, which typically produces semi-lenticular preform protrusions, such as water droplets.

If droplets of liquid are deposited on a solid release surface with greater surface energy (or surface tension) than liquid, the liquid will typically wet the solid completely with a contact angle of zero if given enough time. For liquids, each "solid-liquid" pair has a contact angle of 0 to 180 degrees, whereby the liquid droplets will almost wet the solid. For semi-liquids, for example softened thermoplastic particles, the process of forming a contact angle is a time-temperature phenomenon. For the contact release surface, a large surface energy will allow the particles to wet more quickly, but finally it will be more difficult to separate the contact release surface from the preform protrusions. In addition, if the surface energy of the contact release surface is too large for that of the polymer particles, there is a greater possibility of an operator's unintended mistake of forming a preform protrusion that excessively wets the contact release surface. If the surface energy of the contact release surface is not greater than the first surface energy (that of the particles) plus 60 mJ / m 2, the risk of overwetting the contact release surface is low. The present invention uses nonlinear microstructures (eg, intersecting peaks and / or valleys) to alter this process by stopping the polymer flow across the disengaging surface. The polymer flow can be interrupted and / or partially redirected, allowing a larger surface energy release surface to be used which is less likely to be excessively wetted.

As discussed herein, to control the spreading of the edges of the preform protrusions (and thus to control the size and shape of the preform protrusions), and when removing the preform protrusions from the contact surface. To control ease, the use of surface energy (ie, wettability properties) of a relatively smooth release surface is not the only possible approach. In the present invention, the use of nonlinear microstructured contact release surfaces has been found to be advantageous. Such methods allow microstructured features to have a "speed bump" effect, i.e., features (eg, peaks, ridges, grooves, valleys, depressions, ruts, furrows, posts). (posts, wells, holes, knobs, nodules, etc.) take advantage of the fact that they may have the effect of having a tendency to inhibit the flow or diffusion of liquids.

Thus, it is useful to provide a contact release surface with nonlinear microstructured features that do not allow any lateral orientation (ie along the face of the contact release surface) without a physical flow barrier. . Such nonlinear microstructures include any that are not limited to fully linear uninterrupted features (eg, continuous linear parallel grooves), and wherein the flowable liquid contacts in any direction without encountering the microstructured features. It includes any that can not move laterally along the release surface, for example more than 0.5 mm. It should be noted that such features do not need to provide a complete barrier to stop, stop or minimize fluid flow. That is, even if interrupted by a gap, if the gap is small enough (eg, in the range of about 200 micrometers or less), discrete features (eg, posts or holes) can still be provided as flow blockers. .

The features may protrude upward from the contact release surface (and thus form microstructured features projecting inwardly on the upper surface of the fastening protrusions formed therefrom), or may protrude downward into the contact release surface (and thus therefrom). Forming an outwardly projecting feature on the upper surface of the fastening protrusion being formed). Such features may have a vertical dimension (eg, height or depth) of about 5 micrometers to about 300 micrometers or more. Accordingly, such features may include a plurality of nonlinear protrusions or indentations, including: patterns with linear cross hatched peaks, ridges and / or valleys; Intersecting peak and / or valley structures, such as pyramidal or microprism or so-called cube corner structures; And the like. Such nonlinear microstructures may also exist locally linear and / or parallel structures but nevertheless move in any lateral direction along the surface of the disengaging surface, eg greater than 0.5 mm, without encountering a fluid barrier. Include things that make it impossible. Such structures include, for example, discontinuous ridges or valleys; Circular concentric ridges or valleys; Ridges or valleys present as sigmoidal curves; And the cross hatch structure described above interrupted by features in which parallel features intersect.

Such microstructured surfaces are preferably engineered or designed rather than produced by a random method (eg, by random deposition of particles, or by abrasion or roughening). It may be a surface. In one embodiment, the microstructured features are provided as regular or repeating feature arrays.

Such microstructured features on the contact release surface can form complementary features on the upper surface of the preform protrusions and consequently on the fastening protrusions thus formed. (These features may not be their exact mirror image on the contact release surface, because liquid may not fully wet and / or fill the contact release surface features, or the formed features may remove the fastening protrusions from the contact release surface. May be distorted in the process). The presence of microstructured physical flow barriers on all lateral release surfaces (as opposed to essentially flat release surfaces) is considerably greater in height vs diameter, as detailed in Example 1 below. It has been found to form preform protrusions (and thus fastening protrusions formed therefrom) having an aspect ratio. That is, this approach tends to provide longer and thinner fastening protrusions than approaches using relatively flat and smooth contact release surfaces. Such fastening protrusions can have significant advantages in terms of the ability of the protrusions to fasten to the fibrous substrate. Such fastening protrusions may also provide easier release of the protrusions from the contact release surface. In one embodiment, the fastening protrusions of the present invention exhibit a height to diameter aspect ratio of at least about 0.7. In another embodiment, the fastening protrusions of the present invention exhibit a height to diameter aspect ratio of at least about 1.0.

The selection of the microstructured features can be combined with the selection of the materials that form the release contact surface to provide additional control over the flow and diffusion properties of the liquid thereon. Surface coatings may also be applied to the features for the same purpose. Such surface coatings may also enhance the ability to remove the solidified preform protrusions from the contact release surface.

An exemplary nonlinear pyramidal microstructured contact release surface is shown in the scanning electron micrograph of FIG. 3. Another exemplary nonlinear microstructured contact release surface that may be useful in the method of the present invention is shown in the figures of FIGS. 6A-6C and the SEM micrograph of FIG. 7.

In the methods described above with respect to the thermoplastic preform protrusions, which may also be referred to collectively as protrusions, the fixing of the distal end of at least some of the preform protrusions and the front surface of the base may be fixed by heat or fusion. It may be preferred if included.

Thermal fixation may include melting either the preform protrusions or the base front surface, depending on material, pressure, and the like. Preferably, both the preform protrusions and the front surface of the base are allowed to potentially melt and thereby be fused. The particles must liquefy sufficiently to adequately form the contact angle during fusion, but must remain solid enough to maintain their edge angle on the contact release surface. It is preferred that the thermoplastic polymer particles have a melt flow rate of 1 to 90 grams per 10 minutes under conditions appropriate for the selected polymer.

In a subsequent step of the method, thermally fixing includes contacting the front surface of the base with the attachment end of at least some of the preform protrusions while maintaining the contact release surface at a temperature below the softening temperature of the polymer particles or preform protrusions. Include. The back surface of the base is preferably heated by applying heated gas thereto. However, other heating methods can be used, such as radiation or IR heat. When a heated gas is used, the gas pressure at the rear surface of the heated base is typically higher than the pressure at the front surface of the heated base (eg, gas pressure), and thus the preform protrusions Pressing at the distal end of at least some of them improves its fixation to the base. The pressure difference can be enhanced, for example, by applying a vacuum from below the front surface of the contact release surface or base.

Another object of the present invention is to provide a new fastener product with corresponding advantages, which is easily attainable through the above methods.

The article of the invention is a fastener for fastening with a loop fabric, wherein the sheet-shaped base has a front surface with a plurality of solids, preferably essentially solid or rigid fastening protrusions. The fastening protrusion has a top end and an attachment end (which may also be referred to overall as a foot). The attachment end is coupled to the base front surface at the fixed portion. Since the fastening protrusions are fixed to the front surface of the base, the base and the fastening protrusions may be formed of different materials or the same material. At least one fastening protrusion protruding from the base front surface may be formed to have a structured surface formed by the structured contact release surface. The top will also generally overhang at least partially on the base, where the overhang portion is also referred to as the rim.

The top of the fastening protrusion thus formed will also have a clear edge which generally defines the top boundary. The fastening protrusion will also have a mantle surface extending from the edge of the top to the attachment end of the fastening protrusion at the front surface of the base, which meets the top along the edge. The mantle surface and the top surface are generally joined to form an acute edge angle along the edge of the cube.

In use, the fastening protrusions will behave essentially like a solid body fixed to a base that is preferably flexible. As used herein, the net convex contour of the fastening protrusion in the lateral appearance is convex and not straight when viewed from the outside. The net convex shape of the bottom surface or mantle surface of the overhang rim has been found to be advantageous because it provides a relatively large thickness in at least one fastening protrusion. In at least one side appearance of the at least one fastening protrusion, the mantle surface is preferably convex at least in its part adjacent to the edge. This convex shape provides strength to the edge of the rim overhanging the base. The convex shape also effectively guides the fastening fibers down towards the base, reducing the torque loads on the fastening protrusions and the base to which they are attached, as discussed above. In another preferred embodiment, the fastening protrusion is forward tapered from the top to the front surface of the base in at least one side appearance of the at least one fastening protrusion.

The fastening protrusion may be forward convex or forward tapered from the top of the protrusion to the front surface of the base in at least one side appearance of the mantle surface. The mantle surface and the top surface of the fastening protrusion define an edge angle. These edge angles are advantageously along the entire edge and may have an angle of about 20 ° to about 85 ° or about 30 ° to about 80 °.

The material of the front surface of the base may be different from the material of at least one fastening protrusion mantle surface attached thereto. Such a configuration can be achieved by the use of a base film and a preform protrusion consisting of different materials, with the use of a compatibilization layer if necessary. It may be even more advantageous if the material of the front surface of the base is softer than the material of the mantle surface of the at least one fastening protrusion, for example as determined by varying the Shore hardness value.

In addition, where the fastener base is elastically stretchable in the plane of the base and the material of the mantle surface of the at least one fastening protrusion is not an elastomer, it may be advantageous for some applications. The base may comprise an elastomeric material including an elastic laminate or the like. This can produce elastic fastener products, which can be particularly beneficial, for example, for diapers and packaging tapes.

The fasteners of the present invention may also be formed on the surfaces of various base materials. This may be the film described above, but may be any suitable surface, such as fabric, nonwoven, metal sheet or foil, molded plastic, paper, breathable film, laminate, and the like, as described above for the first method.

Description of Exemplary Deposition Methods

Reference is made to the method shown in FIG. 1. Using the first subset method of the present invention, polymer powder granules are provided as polymer particles 36. The base 4 sheet is transferred into the system from a suitable source. A contact release surface 40 is provided on a release conveyor 39 driven around two drive rollers 11. The contact release surface 40 is kept horizontal. The contact release surface may have microstructured features as described elsewhere herein.

At the start of the operating cycle, the horizontal contact release surface 40 is maintained at an elevated temperature by the hot plate 24. This may be done below the release conveyor 39, but additional hot chambers on the top side of the release conveyor may also be used. Dispersion unit 42 is used to evenly distribute the polymer particles 36 onto the disengaging contact surface 40. (Optionally, disperse the particles onto a stationary mask 31, such that the solid area of the mask intersects the falling particles and the open surface of the mask moves the particles 40). Drop onto a predetermined pattern). The particles are distributed onto the contact release surface 40 to form the preform protrusions 37. The release surface 40 can be cooled before the heating element 24. Cooling is also important for the later preservation of the contact angle of the preform protrusions 37 and can be provided by the steel cooling plate 45 at a controlled temperature below the contact release surface 40. The cooled preform protrusion 44 becomes solid and is suitable for contact with the front surface 20 of the base 4. Base 4 rests on preform protrusion 44 on release contact surface 40. The front surface 20 of the base 4 is in contact with the distal end of the preform protrusion 44. A hot air blowing unit 23 can be secured on the rear surface 3 of the base 4. The hot gas 21 is blown onto the rear surface 3 of the base 4, which can be done while the release conveyor 39 and the base 4 move together in the lateral direction 25. Each point of the base 4 is exposed to hot air for a time sufficient to soften the distal end of the preform protrusion 44 and the front surface 20 of the base 4 and secure them to each other. The base is then cooled, which can be done by the air blower 12. The base 4, to which the fastening protrusion 13 is fixed, is separated and removed from the contact release surface 40 and then wound onto a reel (not shown).

The fastening protrusion 13 formed using this method will have an upper surface with microstructured features (given by the microstructured features of the contact release surface), wherein the rim typically has a base in all directions ( Overhang in 4), the angle of which is typically bounded around the perimeter by an edge corresponding to the contact angle. Most of the fastening protrusions will be tapered (pure-convex) from the microstructured top to the attachment end in the front surface 20 of the base 4 in its respective side appearance.

Other deposition methods are also possible as described elsewhere herein.

Example 1 Deposition Method of Particles with Microstructured Top Surface

An apparatus similar to that shown in FIG. 1 was used. A contact release surface (shown in FIG. 3) was provided comprising a nickel plate with a pattern of pyramidal microstructured features including intersecting peaks and valleys. The release contact surfaces with these microstructures were prepared in a manner similar to the method described in US Pat. No. 4,488,258, which is incorporated herein by reference. The contact release surface was coated with a fluorine-based benzotriazole compound similar to that described in US Pat. No. 6376065, incorporated herein by reference. A contact release surface was provided as a horizontal sheet on the upper surface of the moving shuttle that could be moved laterally to simulate the continuous belt conveyor system of FIG. 1.

High-density polyethylene particles (available under the name Rowalit N100-20 from Rowak AG, Zurich, Switzerland) ranging in size from about 80 to 200 micrometers in diameter, with gravity-operated spreading units (feed wheels) And a hopper with a bottom screen.

At the beginning of the operating cycle, the horizontal contact release surface was brought to a temperature of about 170 ° C. by a heating element located below the conveyor shuttle. The shuttle was laterally moved at a speed of approximately 0.17 meters per second below the scattering unit used to evenly distribute the polymer particles onto the heated contact release surface at an average density of about 16 g / m 2. No mask was used. The particles were heated by the heat of the contact release surface to soften or melt to a semi-liquid state. A few seconds after the particles were distributed on the release surface, they formed the preform protrusions as described above. The release surface was then cooled down by using a shuttle conveyor to move the release surface over the cooling plate and stop in place to lower the temperature to about 70 ° C. This made the preform protrusions solid, making them suitable for contact with the front surface of the base film.

A base film was provided comprising a high density polyethylene film having a basis weight of 30 g / m 2. The base film was placed on the preform protrusion on the contact release surface such that the front surface of the base is in contact with the distal end of the preform protrusion. Air was blown against the back surface of the base at a measured temperature of about 600 ° C. using a hot air blowing unit fixed above about 15 mm of the back surface of the base film. The release contact surface with the preform protrusion and the shuttle carrying the base film were laterally moved under the hot air blowing unit at approximately 0.17 meters per second. Thus, each point of the base was exposed to hot air for a short period of time (typically 1 second or less), allowing the base to soften sufficiently to be secured to the distal end of the preform protrusion. The distal end was also melted by heat to a suitable extent to fuse the preform protrusions to the base. The base film and the protrusions attached thereto were then cooled. The base and fastening protrusions secured thereto were then removed from the contact release surface together.

The fastening protrusion thus formed had a microstructured top surface (as shown in FIGS. 4A and 4B).

Comparative Example 2: Deposition of Particles Without Microstructured Top Surface

kft)로부터 켐글라스(Chemglas) 100-6이라는 명칭으로 입수가능한, 약간 텍스처형성된(textured) 표면을 갖는, 폴리테트라플루오로에틸렌 코팅된 유리 섬유 웨브를 포함하는 접촉 해제 표면을 제공하였다. 접촉 해제 표면(40)의 표면 에너지는 약 18.5 mJ/㎡이었다. 도 1의 연속 벨트 컨베이어 시스템을 모사하기 위해 측방향으로 이동될 수 있는 셔틀의 상부 표면 상에 접촉 해제 표면을 수평 시트로서 제공하였다.An apparatus similar to that shown in FIG. 1 was used. Loerinz KFtty, Hungary

kft) to provide a contact release surface comprising a polytetrafluoroethylene coated glass fiber web with a slightly textured surface available under the name Chemglas 100-6. The surface energy of the contact release surface 40 was about 18.5 mJ / m 2. A contact release surface was provided as a horizontal sheet on the top surface of the shuttle that could be moved laterally to simulate the continuous belt conveyor system of FIG. 1.

High-density polyethylene particles (available under the name Rovalit N100-20 from Lobac AG, Zurich, Switzerland) ranging in size from about 80 to 200 micrometers in diameter, are gravity-operated scattering units (hopper with transfer wheel and bottom screen). ).

At the beginning of the operating cycle, the horizontal contact release surface was brought to a temperature of about 170 ° C. by a heating element located below the conveyor shuttle. The shuttle was laterally moved at a speed of approximately 0.17 meters per second below the scattering unit used to disperse the polymer particles on the heated contact release surface at an average density of about 16 g / m 2 in the particle deposited area. The particles were heated by the heat of the contact release surface to soften or melt to a semi-liquid state. A few seconds after the particles were distributed on the release surface, they formed preform protrusions. The release surface was then cooled over the cooling plate and stopped in place to cool the contact release surface to a temperature of about 70 ° C. This made the preform protrusion solid, making it suitable for contact with the front surface of the base film.

A base film was provided comprising a polypropylene film having a basis weight of 74 g / m 2 (available under the trade name FL-3054 from 3M Company, St. Paul, Minn.). The base film was placed on the preform protrusion on the contact release surface such that the front surface of the base is in contact with the distal end of the preform protrusion. Air was blown against the back surface of the base at a measured temperature of about 600 ° C. using a hot air blowing unit fixed above about 15 mm of the back surface of the base film. The release contact surface with the preform protrusion and the shuttle carrying the base film were laterally moved under the hot air blowing unit at approximately 0.17 meters per second. Thus, each point of the base was exposed to hot air for a short period of time (typically 1 second or less), allowing the base to soften sufficiently to be secured to the distal end of the preform protrusion. The distal end was also melted by heat to a suitable extent to fuse the preform protrusions to the base. The base film and the protrusions attached thereto were then cooled. The base and fastening protrusions secured thereto were then removed from the contact release surface together.

analysis

As shown in FIG. 5, the average height 51 and the average diameter 52 (on top) of the plurality of fastening protrusions of the samples of Example 1 and Comparative Example 2 were measured. The height / diameter aspect ratio was then calculated for the two types of fastening protrusions, which are shown in Table 1.

All patents, patent applications, and publications cited herein are hereby incorporated by reference in their entirety as if individually incorporated by reference. All numbers are assumed to be modified by the term 'about'. Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope of this invention, and it is to be understood that this invention is not unduly limited to the exemplary embodiments described herein.

Claims (16)

As a hook fastener that can be engaged with a suitable loop fabric, A base substrate having a top surface and a surface having a plurality of fastening protrusions having an attachment end, the attachment end being coupled to the surface of the base substrate at a bond connection, wherein the top surface of at least some of the fastening protrusions And hook fasteners in which intersecting peak and / or valley structures are formed. The hook fastener of claim 1 wherein at least some of the peak structures are discrete structures surrounded by valley structures. 3. The hook fastener of claim 2 wherein at least some of the discrete peak structures are in contact with a material of the upper surface at three or more sides at different heights. The hook fastener of claim 1 wherein at least some of the valley structures are discrete valley structures surrounded by a peak structure. The hook fastener of claim 1, wherein at least some of the peak structures intersect at one or more locations. The hook fastener of claim 1, wherein at least some of the valley structures intersect at one or more locations. The hook fastener of claim 1, wherein at least some of the top surfaces of the fastening protrusion are oval shaped. The hook fastener of claim 1 wherein the top surface structure has a height of at least about 20 micrometers. The hook fastener of claim 1 wherein the top surface structure has a height of at least about 50 micrometers. The hook fastener of claim 1, wherein at least some of the top surfaces of the fastening protrusion are non-elliptical in shape. The hook fastener of claim 1, wherein at least some of the upper surfaces of the fastening protrusions have at least one edge having a mantle surface that forms an angle of at least about 20 degrees. The hook fastener of claim 1, wherein at least some of the upper surfaces of the fastening protrusions have at least one edge with a mantle surface that forms an angle of at least about 30 degrees. A hook fastener that can be engaged with a suitable loop fabric, A base substrate having a top surface and a surface having a plurality of fastening protrusions having an attachment end, the attachment end being coupled to the base substrate at a bond connection, the top surface of at least some of the fastening protrusions being non-linear. A hook fastener comprising microstructured features, the fastening protrusions having nonlinear microstructured features having an average height to diameter aspect ratio of at least about 0.7. The hook fastener of claim 13, wherein the fastening protrusion has an average height to diameter aspect ratio of at least about 1.0. The hook fastener of claim 13, wherein the nonlinear microstructured feature has a height of at least about 20 micrometers. The hook fastener of claim 13, wherein the nonlinear microstructured feature has a height of at least about 50 micrometers.

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