阅读说明：本技术 哑光阻燃标签 (Matte flame-retardant label ) 是由 吕仲菲 杨宇润 谢曙辉 沈骠 王宇 周福海 于 2019-02-02 设计创作，主要内容包括：本文提供了一种适用于标记电气装置的阻燃标签。所公开的标签包括涂层、膜层、粘合层,以及可选的衬里层。涂层和粘合层可包括阻燃剂。阻燃标签还可包括在施加标签期间提供空气排出的通道。(A flame retardant label suitable for labeling an electrical device is provided herein. The disclosed label includes a coating layer, a film layer, an adhesive layer, and an optional liner layer. The coating and bonding layers may include a flame retardant. The flame retardant label may also include channels that provide for air venting during label application.)

1. A flame retardant label, comprising:

a coating comprising a first base polymer, a first crosslinker, and a first flame retardant;

a film layer; and

an adhesive layer comprising a second base polymer, a second flame retardant, a tackifier, and a second crosslinker.

2. The flame retardant label of claim 1 wherein the adhesive layer is in contact with at least a portion of the film layer.

3. The flame retardant label of any one of the preceding claims, wherein each of the coating layer, the film layer, and the adhesive layer comprises a top surface and a bottom surface.

4. A fire retardant label according to any preceding claim, wherein the adhesive layer defines a channel for air egress.

5. A fire retardant label according to any one of claim 4, wherein the channels are arranged as tessellated diamonds.

6. A flame retardant label according to any preceding claim wherein the flame retardant label has a haze value of from 5 to 80.

7. The flame retardant label according to any one of the preceding claims, wherein the first base polymer comprises a polyester, a polyacrylate, or a combination thereof.

8. The flame retardant label of any one of the preceding claims, wherein the coating comprises a polyester, a polyacrylate, or a combination thereof in an amount of 20 wt.% to 60 wt.%.

9. A flame retardant label according to any preceding claim wherein the first base polymer has a hydroxyl number of greater than 100 mgKOH/g.

10. The flame retardant label according to any one of the preceding claims, wherein the second base polymer comprises a polyester, a polyacrylate, or a combination thereof.

11. A flame retardant label according to any preceding claim wherein the second base polymer has a hydroxyl number of less than 100 mgKOH/g.

12. A flame retardant label according to any preceding claim, wherein the second base polymer has an acid number of less than 100 mgKOH/g.

13. A flame retardant label according to any preceding claim wherein the second base polymer has a glass transition temperature of-50 ℃ to 10 ℃.

14. A flame retardant label according to any preceding claim wherein the weight ratio of tackifier to second base polymer in the adhesive layer is from 1: 10 to 1.5: 1.

15. A fire retardant label according to any preceding claim, wherein the first cross-linking agent comprises an isocyanate.

16. The flame retardant label according to any one of the preceding claims, wherein the first flame retardant comprises an organic phosphinate.

17. The flame retardant label according to any one of the preceding claims, wherein the second flame retardant comprises an organic phosphinate.

18. A flame retardant label according to any preceding claim wherein the tackifier in the adhesive layer has an average softening point of less than 125 ℃.

19. The flame retardant label of any one of the preceding claims wherein the tackifier in the adhesive layer comprises rosin, terpene, AMS, coumarone, or derivatives thereof, or combinations thereof.

20. The flame retardant label of any one of the preceding claims, wherein the second crosslinker comprises an isocyanate, an epoxy, or a combination thereof.

21. A flame retardant label according to any preceding claim, wherein the film layer comprises one or more resins selected from the group consisting of: polyesters, ABS, polyacrylates, Polycarbonates (PC), polyamides, Polyimides (PI), polyamideimides, polyacetals, polyphenylene oxides (PPO), polysulfones, Polyethersulfones (PES), polyphenylene sulfides, Polyetheretherketones (PEEK), Polyetherimides (PEI), metallized polyethylene terephthalate (PET), polyvinyl fluoride (PVF), polyvinyl ethers (PEE), Fluorinated Ethylene Propylene (FEP), Polyurethanes (PUR), liquid crystal polymers (LCP, aromatic polyesters), polyvinylidene fluoride (PVDF), aramid fibers, DIALAMY (polymer alloys), polyethylene naphthalate (PEN), ethylene/tetrafluoroethylene (E/TFE), polyphenylsulfones (PPSU).

22. A fire retardant label according to any preceding claim, wherein the coating has a thickness of 1 to 30 μm.

23. A flame retardant label according to any preceding claim wherein the film layer has a thickness of 10 to 60 μm.

24. A flame retardant label according to any preceding claim wherein the adhesive layer is applied at a weight of 5 to 50g/m²。

25. A fire retardant label according to any preceding claim, wherein the fire retardant label has a flammability rating of VTM-0.

26. A fire retardant label according to any preceding claim, wherein the bottom surface is the surface facing the object to be labelled and the top surface is the surface on the opposite side of the bottom surface.

27. A fire retardant label according to any preceding claim, wherein the label further comprises a liner layer in contact with the bottom surface of the adhesive layer.

28. The flame retardant label of claim 27 wherein the backing layer is coated at a weight of 50 to 150g/m²。

29. A fire retardant label according to claim 27 or 28, wherein the liner layer comprises embossed plastic paper.

30. A fire retardant label according to any one of claims 27 to 29 wherein the liner layer comprises cellophane, kraft or other paper coated with a liner polymer.

31. The flame retardant label of claim 30 wherein the liner polymer is coated at a weight of 5 to 50g/m²。

32. A flame retardant label according to any preceding claim, wherein the coating comprises a polyester in an amount of 25 to 40 wt.%; wherein the first base polymer has a hydroxyl number of greater than 100 mgKOH/g; wherein the second base polymer has a hydroxyl value of less than 80mgKOH/g and an acid value of less than 35 mgKOH/g; wherein the second base polymer has a glass transition temperature of-40 ℃ to 0 ℃; and wherein the flame retardant label has a flammability rating of VTM-0.

33. A flame retardant label according to any preceding claim wherein the coating layer has a thickness of 5 to 15 μm, the film layer has a thickness of 20 to 30 μm and the adhesive layer is applied in an amount of 15 to 25g/m²。

34. A flame retardant label according to any preceding claim wherein the first crosslinker comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; the tackifier comprises terpene or rosin; and the second crosslinking agent comprises an isocyanate or an epoxy resin.

35. A flame retardant label according to any preceding claim wherein the first crosslinker comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; the tackifier comprises terpene or rosin; the second crosslinking agent comprises isocyanate or epoxy resin; and wherein the flame retardant label has a flammability rating of VTM-0.

36. A flame retardant label according to any preceding claim wherein the flame retardant label is attached to a battery surface or battery packaging.

37. A method of labeling a battery comprising the steps of:

providing a flame retardant label comprising:

a coating comprising a first base polymer, an isocyanate crosslinker, and a first flame retardant;

a film layer; and

an adhesive layer comprising a second base polymer, a second flame retardant, a tackifier, and a second crosslinker; and

attaching the flame retardant label to a battery surface or a battery package.

Technical Field

The present disclosure relates generally to flame retardant labels. These tags can be used to label electrical devices, such as batteries.

Background

Flame retardant labels are needed in many cases, including labeling of electrical devices such as lithium ion batteries. Electrical equipment may increase the risk of fire, for example, due to its long-term use or operation, and therefore labels and their components with flame retardant capabilities are needed. The labels also require good printability and good adhesive properties for full use with electrical equipment. Adhesive performance is typically measured by bond strength, shear force, and/or 180 ° peel strength. In addition, the label must also be of a suitable size and thickness so that the label can be easily wrapped around a given substrate. Furthermore, the amount of components present in the layers of the label must be controlled so that the manufacture of the label remains cost-effective.

Generally, labels having flame retardant properties are manufactured by stacking multiple layers of flame retardant coatings, films and adhesives. The coatings of some conventional labels typically include polymeric resins that lack sufficient resistance to thermal decomposition, e.g., having a low char yield. The char yield of the polymer is defined as the residual amount of solids at 930 ℃ in a nitrogen atmosphere, and in general, a higher char yield is associated with a higher thermal decomposition resistance and a higher flame retardant ability. In some cases, a flame retardant may be added to the topcoat to improve its flame retardant properties. However, flame retardants added to labels often affect the adhesive properties of the label. Therefore, to compensate for the problems with flame retardants, manufacturers typically increase the amount of other ingredients in the different layers that contribute to the adhesive properties of the label and increase the thickness of the label. Disadvantageously, these adjustments often result in increased manufacturing costs and inconvenience in label application. Furthermore, the resulting labels can often be too thick for the intended purpose.

Conventional labels are also particularly susceptible to entrapment of air bubbles during application. For example, when a label is applied to a substrate, such as a piece of electrical equipment, air vortices may become entrained between the label and the substrate, and if the air vortices are completely surrounded by the label, non-movable air bubbles may form. The air bubbles entrained by the label may be unsightly and may distort the image or text printed on the reverse side of the label. Furthermore, air bubbles may interfere with the structural design. For example, if the entrained air bubbles artificially increase the surface area and/or volume of a piece of tagged electrical equipment, the tagged electrical equipment may not be securely mounted in the intended location. Particularly with regard to flame retardant labels, the bubbles can form part of the substrate to which the label is applied without sufficient flame retardant capability. Thus, the bubbles may increase the risk of fire, thereby destroying the intended activity of the flame retardant label.

Even in view of conventional labels, there remains a need for cost-effective labels having effective and stable flame retardant properties while having a suitable thickness and good adhesion, conversion and/or repositioning properties. In particular, there is a need for a label that has these characteristics and also allows air to escape so that no air bubbles are formed during application.

Disclosure of Invention

In one embodiment, the present invention relates to a flame retardant label comprising: a coating comprising a first base polymer, a first crosslinker, and a first flame retardant; a film layer; and an adhesive layer including a second base polymer, a second flame retardant, a tackifier, and a second crosslinking agent. In certain embodiments, the adhesive layer is in contact with at least a portion of the film layer. In certain embodiments, each of the coating layer, the film layer, and the adhesive layer includes a top surface and a bottom surface. In certain embodiments, the adhesive layer defines a channel for air egress. In some cases, the channels may be arranged as tessellated diamonds. In certain embodiments, the flame retardant label has a haze value of 5 to 80.

In certain embodiments, the first base polymer comprises a polyester, a polyacrylate, or a combination thereof. The coating may include a polyester, a polyacrylate, or a combination thereof in an amount of 20 wt.% to 60 wt.%. The first base polymer may have a hydroxyl value of greater than 100 mgKOH/g. In certain embodiments, the second base polymer comprises a polyester, a polyacrylic acidAn ester, or a combination thereof. The second base polymer may have a hydroxyl value of less than 100 mgKOH/g. The second base polymer may have an acid value of less than 100 mgKOH/g. In certain embodiments, the second base polymer has a glass transition temperature of-50 ℃ to 10 ℃. In certain embodiments, the weight ratio of tackifier to second base polymer in the adhesive layer is from 1: 10 to 1.5: 1. In certain embodiments, the first crosslinker comprises an isocyanate. In certain embodiments, the first flame retardant comprises an organic phosphinate. In certain embodiments, the second flame retardant comprises an organic phosphinate. In certain embodiments, the tackifier in the adhesive layer comprises rosin, terpene, or derivatives thereof, or combinations thereof. The tackifier in the adhesive layer may have an average softening point of less than 125 ℃. In certain embodiments, the second crosslinker comprises an isocyanate, an epoxy, or a combination thereof. In certain embodiments, the film layer comprises one or more resins selected from the group consisting of: polyesters, ABS, polyacrylates, Polycarbonates (PC), polyamides, Polyimides (PI), polyamideimides, polyacetals, polyphenylene oxides (PPO), polysulfones, Polyethersulfones (PES), polyphenylene sulfides, Polyetheretherketones (PEEK), polyetherimides (PE1), metallized polyethylene terephthalate (PET), polyvinyl fluoride (PVF), polyvinyl ethers (PEE), Fluorinated Ethylene Propylene (FEP), Polyurethanes (PUR), liquid crystal polymers (LCP, aromatic polyesters), polyvinylidene fluoride (PVDF), aramid fibers, DIALAMY (polymer alloys), polyethylene naphthalate (PEN), ethylene/tetrafluoroethylene (E/TFE), polyphenylsulfones (PPSU). In certain embodiments, the coating has a thickness of 1 to 30 μm. The thickness of the film layer may be 10 to 60 μm. In certain embodiments, the adhesive layer is applied at a weight of 5 to 50g/m². In certain embodiments, the flame retardant label has a flammability rating of VTM-0. In some embodiments, the bottom surface is the surface facing the object to be labeled, and the top surface is the surface on the opposite side of the bottom surface.

In certain embodiments, the flame retardant label further comprises a liner layer in contact with the bottom surface of the adhesive layer. In these examples, the coating weight of the backing layer is 50 to 150g/m². The backing layer of these embodiments may comprise embossed plastic paper. These fruitsThe liner layer of an embodiment comprises a glassine paper coated with a liner polymer. The coating weight of the lining polymer can be 5 to 50g/m²。

In certain embodiments, the coating comprises a polyester in an amount ranging from 25 wt.% to 40 wt.%; the first base polymer has a hydroxyl value of greater than 100 mgKOH/g; the second base polymer has a hydroxyl value of less than 80mgKOH/g and an acid value of less than 35 mgKOH/g; the second base polymer has a glass transition temperature of-40 ℃ to 0 ℃; and the flammability rating of the flame retardant label meets VTM-0. In certain embodiments, the thickness of the coating layer is 5 to 15 μm, the thickness of the film layer is 20 to 30 μm, and the coating amount of the adhesive layer is 15 to 25g/m². In certain embodiments, the first crosslinker comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; tackifiers including terpenes or rosins; and the second crosslinker comprises an isocyanate or an epoxy resin. In certain embodiments, the first crosslinker comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; tackifiers including terpenes or rosins; the second crosslinking agent comprises isocyanate or epoxy resin; and the flammability rating of the flame retardant label meets VTM-0.

In certain embodiments, the flame retardant label is attached to a battery surface or battery packaging.

The invention also provides a method for labeling a battery, which comprises the following steps: (i) providing a flame retardant label comprising: a coating comprising a first base polymer, an isocyanate crosslinker, and a first flame retardant; a film layer; and an adhesive layer comprising a second base polymer, a second flame retardant, a tackifier, and a second crosslinking agent; and (ii) attaching the flame retardant label to a battery surface or battery packaging.

Drawings

Embodiments are described in detail below with reference to the drawings, wherein like numerals represent like parts.

Fig. 1 shows a cross-section of a flame retardant label having a coating layer, a film layer, and an adhesive layer, according to an embodiment.

Figure 2 shows a front view of the top surface of the backing layer with the ridge.

Detailed Description

Introduction to the design reside in

As mentioned above, labels for electrical devices such as batteries must be flame retardant to prevent fire hazards. However, the addition of flame retardants to labels can compromise other properties of the label, such as adhesion, conversion and repositioning properties. For example, adding a flame retardant to the adhesive layer may reduce the shear strength of the label, which may cause the label to become brittle. Moreover, the addition of flame retardants to the adhesive layer may adversely affect the adhesive and cohesive strength of the label. In addition, there needs to be sufficient air egress to prevent air bubbles from forming and becoming trapped under the label. It has been found that the addition of flame retardants to conventional labels (to improve flame retardant performance) undesirably reduces the ease of air venting during application. In particular, it has been found that the addition of flame retardants has a negative effect on the ease of flow of the adhesive. Thus, conventional means of making flame retardant labels typically result in labels with insufficient adhesion and insufficient air egress.

The inventors have discovered unique combinations of layers, each layer having a specific composition, providing a flame retardant label that demonstrates flame retardant characteristics as well as a synergistic combination of good adhesion, repositioning and/or converting properties with improved air egress characteristics. The flame retardant label includes at least three layers: a coating layer, a film layer, and an adhesive layer. In certain embodiments, the coating includes a first base polymer, a first crosslinker, and a first flame retardant. In certain embodiments, the adhesive layer comprises a second base polymer, a second flame retardant, a tackifier, and a second crosslinker. Alternatively, the label further comprises a printable layer and/or a backing layer.

It has now been found that in order to minimize the negative effect of the presence of the flame retardant on the adhesive properties of the adhesive layer, in certain cases, epoxy resins can be used as a component of the adhesive layer, for example, as a crosslinking agent. The combination of the epoxy resin and the second flame retardant (in a lesser amount) surprisingly improves the bond strength and flame retardant properties. Conventionally, it has been found that flame retardant performance and adhesive properties are not consistent with each other — an increase in flame retardancy leads to a decrease in adhesive properties, and vice versa. In certain embodiments, the (specific) crosslinking agent is used to increase the cohesiveness of the label. The combination of these crosslinkers, epoxy resin, and second flame retardant (in minor amounts) unexpectedly provides additional improvements in flame retardancy and label performance. In addition, the inventors of the present application have also found that the use of specific concentration ranges for the components provides the desired combination of performance characteristics.

It has also been found that the formation and entrainment of air bubbles between the label and the substrate to which the label is applied can be reduced by including air evacuation passageways in the label (and by using a particular adhesive layer composition having a low level of flame retardant). In particular, the flame retardant label may be configured to define a channel, for example in the adhesive layer, allowing for efficient air venting. The channel creates a path through which air trapped between the label and the substrate can pass, thereby preventing the formation of air bubbles and allowing the effective removal of air bubbles. Advantageously, the use of air evacuation channels in conjunction with certain layers provides a label that advantageously has desirable haze characteristics, such as haze values in the range of 5 to 80, since the channels also contribute to scattering of light passing through the label. Importantly, a lower amount of flame retardant may advantageously affect (e.g., increase) the flowability of the layer, thereby unexpectedly improving air egress through the air egress channels.

Structure of the product

As described above, the flame retardant label includes three layers: a coating layer, a film layer, and an adhesive layer. In certain embodiments, the layer of the adhesive label is arranged such that at least a portion of the film layer is in contact with the adhesive layer. In certain embodiments, the layer of the adhesive label is arranged such that at least a portion of the film layer is in contact with the coating layer. In some cases, the layers of the flame retardant label are arranged such that at least a portion of the film layer is disposed between the coating layer and the adhesive layer. In some cases, the coating, film layer, and adhesive layer are coextensive.

In some cases, other layers may also be included, and the film layer may not necessarily be in direct contact with the other layers. That is, "disposed between" does not necessarily mean "in contact with". As used herein, the term "coextensive" refers to the relationship between two or more layers such that adjacent or parallel-faced surface regions of the layers are aligned with each other with little or no overhang (of at least one region or layer). In some cases, the areas or faces are within 90% of each other. For example, two or more layers are coextensive if the surface areas of adjacent or parallel faces of the layers are within 90%, within 92%, within 94%, within 96%, or within 98% of each other. The term "coextensive" may also refer to a relationship between two or more layers such that the lengths of the layers are within 90% of each other. For example, two or more layers are coextensive if the lengths of the layers are within 90%, within 92%, within 94%, within 96%, or within 98% of each other. The term "coextensive" may also refer to a relationship between two or more layers such that the widths of the layers are within 90% of each other. For example, two or more layers are coextensive if the width of the layers are within 90%, within 92%, within 94%, within 96%, or within 98% of each other.

In certain embodiments, each of the top coating layer, the film layer, and the adhesive layer has opposing top and bottom surfaces, wherein the bottom surface is the surface facing the substrate. In a top view of a tagged electronic device, such as a battery, the film layer may be below the coating layer, e.g., the top surface of the film layer is in contact with the bottom surface of the coating layer, and the film layer may be above the adhesive layer, e.g., the bottom surface of the film layer is in contact with the top surface of the adhesive layer. Other layers may also be present between the coating and the adhesive layer. Without being bound by theory, it is believed that the improvement is seen when (at least a portion of) the coating layer is not in direct contact with (at least a portion of) the adhesive layer, e.g. no contact between the coating layer and the adhesive layer and/or contact of the adhesive layer with at least a portion of the film layer provides a beneficial synergistic effect.

Fig. 1 shows a cross-section of an embodiment of a flame retardant label 100. Flame retardant label 100 includes a coating layer 102, a film layer 104, and an adhesive layer 106, wherein film layer 104 is disposed between coating layer 102 and adhesive layer 106.

In certain embodiments, one or more of the top coating, film layer, and/or adhesive layer may define channels, e.g., irregularities or ridges in the top and/or bottom surfaces of the respective layer. In some cases, the adhesive layer alone comprises a channel. In particular, the bottom surface of the adhesive layer defines a channel in the flame retardant label. The channel creates a path through which air trapped between the label and the substrate can pass, thereby preventing the formation of air bubbles and allowing the effective removal of air bubbles. In other words, the channel acts as a conduit through which air entrained under the label during application can flow to be released.

The size of the channels may vary widely. In one embodiment, the width of the channel ranges from 80 to 200 μm, such as 80 to 180 μm, 80 to 175 μm, 80 to 160 μm, 80 to 150 μm, 90 to 200 μm, 90 to 180 μm, 90 to 175 μm, 90 to 160 μm, 90 to 150 μm, 100 to 200 μm, 100 to 180 μm, 100 to 175 μm, 100 to 160 μm, 100 to 150 μm, 110 to 200 μm, 110 to 180 μm, 110 to 175 μm, 110 to 160 μm, or 110 to 150 μm. In terms of a lower limit, the width of the channel may be greater than 80 μm, such as greater than 90 μm, greater than 100 μm, or greater than 110 μm. In terms of an upper limit, the width of the channel may be less than 200 μm, such as less than 180 μm, less than 175 μm, less than 160 μm, or less than 150 μm.

The average depth of the channels may vary widely, so long as the average depth is less than the thickness of the layer in which the channels are formed. The inventors have found that the choice of the depth of the channel has a significant effect on the flame retardant label, for example by affecting the scattering of light passing through the flame retardant label. In one embodiment, the channels have an average depth in a range from 1 to 25 μm, such as 2 to 25 μm, 3 to 25 μm, 5 to 25 μm, 8 to 25 μm, 1 to 22 μm, 2 to 22 μm, 3 to 22 μm, 5 to 22 μm, 8 to 22 μm, 1 to 20 μm, 2 to 20 μm, 3 to 20 μm, 5 to 20 μm, 8 to 20 μm, 1 to 18 μm, 2 to 18 μm, 3 to 18 μm, 5 to 18 μm, 8 to 18 μm, 1 to 15 μm, 2 to 15 μm, 3 to 15 μm, 5 to 15 μm, or 8 to 15 μm. With respect to the lower limit, the average depth of the channels may be greater than 1 μm, such as greater than 2 μm, greater than 3 μm, greater than 5 μm, or greater than 8 μm. In terms of an upper limit, the average depth of the channels may be less than 25 μm, such as less than 22 μm, less than 20 μm, less than 18 μm, or less than 15 μm.

The creation of channels can vary widely. For example, a channel may be created in a given layer by using a known machine, such as a die cutter. However, creating channels in a given layer using a separate machine may result in inefficient manufacture of the flame retardant label. The inventors have found that, in contrast, when channels are created in a given layer by applying a further layer comprising ridges, the manufacturing efficiency is improved. For example, in embodiments of a flame retardant label that includes a backing layer as described below and is configured such that the bottom surface of the adhesive layer contacts the top surface of the backing layer, the channel in the bottom surface of the adhesive layer may be formed by creating a ridge in the top surface of the backing layer. When the backing layer is removed during application, the ridges of the backing layer remain embossed as channels in the bottom surface of the adhesive layer. Alternatively, the channels may be created by applying the layer to the ridges of the backing layer, e.g. without embossing.

There may be a large difference in the planar design or layout of the backing layer's ridges. In some embodiments, the planar design or layout of the ridges may be randomized lines, curves, or shapes. In other embodiments, the planar design or layout of the ridges may be a regular shape, such as a square, rectangle, diamond, triangle, or circle. In some cases, the planar layout of the ridges may be substantially parallel lines and/or curves. In some cases, the planar layout of the ridges may be lines and/or curves that intersect at substantially regular angles. In one case, as shown in fig. 2, the planar layout 200 of the ridges 202 is an array of tessellated diamonds 204.

Coating layer

The flame retardant label includes a coating. In certain embodiments, the coating is disposed over the film layer. In other words, in certain embodiments, the bottom surface of the coating is in contact with (at least a portion of) the top surface of the film layer.

In one embodiment, the coating of the flame retardant label comprises a first base polymer. The coating may also include a first crosslinking agent and a first flame retardant.

The composition of the first base polymer may vary widely and any suitable polymer may be used so long as the characteristics described herein are met. In certain embodiments, the first base polymer comprises a polyester. In certain embodiments, the first base polymer of the coating can be a polyester polyol, such as a hydroxylated polyester polyol. In some cases, the first base polymer may be an acrylic-modified saturated polyester polyol resin or a polyacrylate polyol.

Examples of suitable commercially available polyester polyols that can be used as the first base polymer include those of DSMSC953、SN862、SY942、SY941、SY944, Hypomer PE-8043 of Elementis, of COVESTRO1300PR、1400PR、PL302、817、RD181、650、651、670、800、850、1100、1145、1150、1155、1200、1300, PERSTORP2043、2054、2085、3050、3091、4101, Synolic 680X60 of ARKEMA.

Examples of suitable commercially available polyacrylate polyols that can be used as the first base polymer include Hypomer FS-2970, Hypomer FS-3060, Hypomer FS-3270, Hypomer FS-4365A, Hypomer FS-4470, Hypomer FS-4660P of ELEMENTCY250、Hybrid of CY240, dsm^TMCY245、Hybrane^TMCY235 from COVESTROA665、A870, Synocure 865EEP 70, Synocure 9237, Synocure 866, Synocure 9201, Synocure 570X 65 and Synocure 9279S 70 of ARKEMA.

In certain embodiments, the first base polymer includes hydroxyl functional groups. The inventors have surprisingly found that hydroxyl functionality can advantageously interact with the first flame retardant, e.g. to form a complex, thereby improving the flame retardant capability of the label.

The presence of hydroxyl functionality in the polymer can be quantified by the hydroxyl number of the polymer, which is the amount of potassium hydroxide required to neutralize the acetic acid absorbed upon acetylation of one gram of polymer containing free hydroxyl groups. In one embodiment, the first base polymer of the coating has a hydroxyl value of greater than 100mgKOH/g, such as greater than 105mgKOH/g, greater than 108mgKOH/g, greater than 110mgKOH/g, or greater than 112 mgKOH/g. With respect to the upper limit, the hydroxyl value of the first base polymer can be less than 350mgKOH/g, such as less than 330mgKOH/g, less than 325mgKOH/g, less than 320mgKOH/g, or less than 300 mgKOH/g. In terms of ranges, the hydroxyl value of the first base polymer is from 100 to 300mgKOH/g, such as 105 to 300mgKOH/g, 108 to 300mgKOH/g, 110 to 300mgKOH/g, 112 to 300mgKOH/g, 100 to 330mgKOH/g, 105 to 330mgKOH/g, 108 to 330mgKOH/g, 110 to 330mgKOH/g, 112 to 330mgKOH/g, 100 to 325mgKOH/g, 105 to 325mgKOH/g, 108 to 325mgKOH/g, 110 to 325mgKOH/g, 112 to 325mgKOH/g, 100 to 320mgKOH/g, 105 to 320mgKOH/g, 108 to 320mgKOH/g, 110 to 320mgKOH/g, 112 to 320mgKOH/g, 100 to 300mgKOH/g, 105 to 300mgKOH/g, 108 to 300mgKOH/g, 110 to 300mgKOH/g, or 112 to 300 mgKOH/g. Without being bound by theory, it is believed that the hydroxyl groups may help prevent the combustion reaction and eliminate or reduce further combustion.

In one embodiment, the coating comprises 20 to 60 wt.%, e.g., 25 to 60 wt.%, 30 to 60 wt.%, 35 to 60 wt.%, 20 to 55 wt.%, 25 to 55 wt.%, 30 to 55 wt.%, 35 to 55 wt.%, 20 to 50 wt.%, 25 to 50 wt.%, 30 to 50 wt.%, 35 to 50 wt.%, 20 to 45 wt.%, 25 to 45 wt.%, 30 to 45 wt.%, or 35 to 45 wt.% of the first base polymer, based on the total weight of the coating. With respect to the lower limit, in certain embodiments of the flame retardant label, the coating layer may include greater than 20 wt.%, such as greater than 25 wt.%, greater than 30 wt.%, or greater than 35 wt.% of the first base polymer, based on the total weight of the coating layer. As an upper limit, in certain embodiments of the flame retardant label, the coating layer may comprise less than 60 wt.%, e.g., less than 55 wt.%, less than 50 wt.%, or less than 45 wt.% of the first base polymer. The amount of the first base polymer may be selected based on the desired stiffness of the coating, the amount of flame retardant present in the coating, and/or the ability to provide sufficient anchoring of the coating on the film layer. Typically, a lower weight percent of the first base polymer and/or a higher weight percent amount of flame retardant is associated with a stiffer flame retardant label. The stiffness of the label may affect the performance characteristics or usability of the label, i.e., the ability to be cut into small labels of the appropriate shape and size.

The coating may also include a first crosslinker. Typically, the crosslinking agent is a substance that forms crosslinks between polymer chains, such as by bonding to each polymer chain. Typically, the addition of a cross-linking agent increases the stiffness or rigidity. The composition of the first crosslinking agent can vary widely. In certain embodiments, the coating includes an isocyanate crosslinker. For example, in certain embodiments, the first crosslinking agent comprises an aromatic isocyanate, an aliphatic isocyanate, an aromatic diisocyanate, an aliphatic diisocyanate, an aromatic polyisocyanate, or an aliphatic polyisocyanate, or a combination thereof.

Examples of suitable commercially available products that may be used as the first crosslinker include COVESTRO (formerly Bayer materials science) Desmodur N75A BA, Desmodur N75A BA/X, Desmodur N100A, Desmodur N3200, Desmodur N3300A, Desmodur N3390A, Desmodur/X N XP 3600, Desmodur N3580, Desmodur N3790 BA, Desmodur PL 3800, Desmodur N3900, Desmodur PL 340 BA/SN, Desmodur NZ1, Desmodur E65, Desmodur E3370, Desmodur PL 350MPA/SN, Desmodur TS 35, Desmodur TS 50, Desmodur VL, Desmodur VP 3254, Desmodur LS 25LS 2551, Desmodur PU 2580, Desmodur VP 2532, Desmodur VP 2580, Desmodur VP 25xp 2580, Desmodur VP 2551, Desmodur VP 25xp 23PU 2580, Desmodur VP 25xp 2380, Desmodur VP 25xp 2551, Desmodur VP 25xp 2580, Desmodur VP 25xp 2551, Desmodur VP 25xp 2380, Desmodur VP 25xp Desmodur XP 2617, Desmodur XP 2675, Desmodur XP 2763, Desmodur XP 2795, Desmodur XP 2838, Desmodur XP 2840, Desmodur Z4470 BA, Desmodur Z4470 MPA/X, Desmodur Z4470 SN/BA, Desmodur IL 1351, Desmodur LD, Desmodur LP BUEJ 471, Mondur 445, Mondur, Basonat HA 100, Basonat HA 200, Basonat HA 300, Luprant M10R, Luprant M20FB, Luprant M20S, Luprant M50, Luprant M70R, Luprant ME 103, Luanprant M103, Luprant M102, Luprant PI 35500, TakePI 36143, Luprant PI 36500, Luprant PI 35500, Luprant PI 500, Luprant PI 3, Luprant PI 500, Luprant PI 3, Luprant PI 500, Luprant PI 3, S35, S7, S3, S7, S3, S11, S3, S11, S3, S2, S11, S3, S11, S3, S11, S2, S3, S11, S3, S11, S3, S2, S3, S2, S3, S2, S3, S2, S3, S2, S1, S3, S1, S3, S1, S3, Takenate D140N, Takenate D160N, Takenate D165N, Takenate D170N, Takenate D178N, Stabio D3725N.

In one embodiment, the coating comprises 10 to 30 wt.%, e.g., 10 to 28 wt.%, 10 to 25 wt.%, 10 to 22 wt.%, 12 to 30 wt.%, 12 to 28 wt.%, 12 to 25 wt.%, 12 to 22 wt.%, 15 to 30 wt.% of the first crosslinking agent, based on the total weight of the coating. 15 to 28 wt.%, 15 to 25 wt.%, 15 to 22 wt.%, 18 to 30 wt.%, 18 to 28 wt.%, 18 to 25 wt.%, 18 to 22 wt.%, 20 to 30 wt.%, 20 to 28 wt.%, 20 to 25 wt.%, or 20 to 22 wt.%. With respect to the lower limit, the coating may comprise greater than 10 wt.%, e.g., greater than 12 wt.%, greater than 15 wt.%, greater than 18 wt.%, or greater than 20 wt.% of the first crosslinker, based on the total weight of the coating. In terms of the upper limit, the coating may comprise less than 30 wt.%, e.g., less than 28 wt.%, less than 25 wt.%, or less than 22 wt.% of the first crosslinker, based on the total weight of the coating.

As described above, the coating may include a first flame retardant. The composition of the first flame retardant may vary widely and any conventional flame retardant may be used so long as the characteristics described herein are met. In certain embodiments, the first flame retardant comprises one or more organic phosphinates. For example, the first flame retardant may include a metal salt of an organophosphinic acid, such as an organophosphinic salt containing magnesium, calcium, aluminum, antimony, tin, titanium, zinc, or iron. In certain embodiments, the first flame retardant may include an organic diphosphinate salt. In some cases, the first flame retardant is an aluminum salt of an organic diphosphinic acid.

Examples of suitable commercially available products that can be used as the first flame retardant include those of ClariantOP series.

In one embodiment, the coating comprises the first flame retardant in an amount of 20 to 60 wt.%, e.g., 25 to 60 wt.%, 30 to 60 wt.%, 35 to 60 wt.%, 20 to 55 wt.%, 25 to 55 wt.%, 30 to 55 wt.%, 35 to 55 wt.%, 20 to 50 wt.%, 25 to 50 wt.%, 30 to 50 wt.%, 35 to 50 wt.%, 20 to 45 wt.%, 25 to 45 wt.%, 30 to 45 wt.%, or 35 to 45 wt.%, based on the total weight of the coating. With respect to the lower limit, in certain embodiments of the flame retardant label, the coating may comprise greater than 20 wt.%, such as greater than 25 wt.%, greater than 30 wt.%, or greater than 35 wt.% of the first flame retardant, based on the total weight of the coating. As an upper limit, in certain embodiments of the flame retardant label, the coating may comprise less than 60 wt.%, e.g., less than 55 wt.%, less than 50 wt.%, or less than 45 wt.% of the first flame retardant.

In one embodiment, the thickness of the coating ranges from 1 to 30 μm, such as 1 to 25 μm, 1 to 20 μm, 1 to 15 μm, 1 to 12 μm, 2 to 30 μm, 2 to 25 μm, 2 to 20 μm, 2 to 15 μm, 2 to 12 μm, 5 to 30 μm, 5 to 25 μm, 5 to 20 μm, 5 to 15 μm, 5 to 12 μm, 8 to 30 μm, 8 to 25 μm, 8 to 20 μm, 8 to 15 μm, or 8 to 12 μm. With respect to the lower limit, the thickness of the film layer may be at least 1 μm, such as at least 2 μm, at least 5 μm, or at least 8 μm. With respect to the upper limit, the thickness of the film layer may be less than 30 μm, such as less than 25 μm, less than 20 μm, less than 15 μm, or less than 12 μm.

Film layer

As described above, the flame retardant label includes at least one film layer. In certain embodiments, the film layer is disposed between the coating layer and the adhesive layer. In certain embodiments, at least a portion of the film layer is in contact with the coating. The film layer may be a polymer film or a metal foil. The material of the film layer may be a resin selected from the group consisting of: polyesters, ABS, polyacrylates, Polycarbonates (PC), polyamides, Polyimides (PI), polyamideimides, polyacetals, polyphenylene oxides (PPO), polysulfones, Polyethersulfones (PES), polyphenylene sulfides, Polyetheretherketones (PEEK), polyetherimides (PEl), metallized polyethylene terephthalate (PET), polyvinyl fluoride (PVF), polyvinyl ethers (PEE), Fluorinated Ethylene Propylene (FEP), Polyurethanes (PUR), liquid crystal polymers (LCP, aromatic polyesters), polyvinylidene fluoride (PVDF), aramid fibers, DIALAMY (polymer alloys), polyethylene naphthalate (PEN), ethylene/tetrafluoroethylene (E/TFE), polyphenylsulfone (PPSU), and polymers or polymer alloys comprising one or more of these materials. In certain embodiments, the film layer has flame retardancy that meets VTM-2, or VTM-0 criteria. In some cases, the film is a polyethylene terephthalate (PET) film. In certain embodiments, the film meets the requirements of VTM-0, VTM-1, or VTM-2. In certain embodiments, the film layer further comprises a flame retardant. Any flame retardant, such as those suitable for use in coatings or adhesive layers as described herein, may be used in the film layer. Used in film layerThe flame retardant may be the same or different than the flame retardant used in the other layers of the flame retardant label. In certain embodiments, the film is a PET film. In certain embodiments, the film is a VTM-0 PET film or a VTM-2 PET film. Various PET Films are available, for example, from Dupont Teijin FilmsSeries of MitsubishiSeries, etc. are commercially available.

The film layer can be disposed below the coating layer, e.g., with a top surface of the film layer in contact with a bottom surface of the coating layer, and the film layer can be disposed above the adhesion layer, e.g., with a bottom surface of the film layer in contact with a top surface of the adhesion layer, from a top view of the substrate. As noted above, it has been found that the configuration of the film layers between the coating layer and the adhesive layer (optionally along with the specific composition of each layer) unexpectedly provides an additional combination of improved flame retardant characteristics and performance characteristics.

In one embodiment, the thickness of the film layer ranges from 10 to 60 μm, such as 10 to 58 μm, 10 to 55 μm, 10 to 52 μm, 10 to 50 μm, 12 to 60 μm, 12 to 58 μm, 12-55 μm, 12 to 52 μm, 12 to 50 μm, 15 to 60 μm, 15 to 58 μm, 15 to 55 μm, 15 to 52 μm, 15 to 50 μm, 20 to 60 μm, 20 to 58 μm, 20 to 55 μm, 20 to 52 μm, or 20 to 50 μm. With respect to the lower limit, the thickness of the film layer may be at least 10 μm, such as at least 12 μm, at least 15 μm, or at least 20 μm. In an upper limit, the thickness of the film layer may be less than 60 μm, such as less than 58 μm, less than 55 μm, less than 52 μm, or less than 50 μm.

Adhesive layer

The flame retardant label includes an adhesive layer. In certain embodiments, the adhesive layer is disposed below the film layer. In other words, in certain embodiments, the top surface of the adhesion layer is in contact with (at least a portion of) the bottom surface of the film layer.

In one embodiment, the adhesive layer of the flame retardant label comprises a second base polymer. The adhesive layer may further include a second flame retardant, a tackifier, and a second crosslinking agent. The composition of the second base polymer can vary widely and any polymer can be used so long as the characteristics described herein are met. In certain embodiments, the second base polymer comprises a polyester or a polyacrylate, or a combination thereof. In some cases, the second base polymer includes an acrylic resin. In certain embodiments, the second base polymer may comprise a pressure sensitive adhesive, such as a hydroxyl-substituted acrylic polymer. Suitable pressure sensitive adhesives may include, for example, copolymers of linear alkyl acrylates having 4 to 12 carbon atoms and small amounts of highly polar copolymerizable monomers such as acrylic acid. In some cases, the second base polymer may be an ultraviolet curable pressure sensitive adhesive.

Examples of suitable commercially available products that can be used as the secondary base polymer include National Starch chemical company80-115A or Duro-Tak 4000, or Aroset from Ashland Specialty Chemicals^TM1860-Z-45。

In certain embodiments, the second base polymer includes hydroxyl functional groups. As mentioned above, the presence of hydroxyl functionality can be quantified by the hydroxyl number of the polymer. In one embodiment, the second base polymer of the adhesive layer has a hydroxyl value of less than 100mgKOH/g, such as less than 95mgKOH/g, less than 90mgKOH/g, less than 85mgKOH/g, or less than 80 mgKOH/g. With respect to the lower limit, the second base polymer may have a hydroxyl value of greater than 0mgKOH/g, such as greater than 2mgKOH/g, greater than 5mgKOH/g, or greater than 10 mgKOH/g. In terms of ranges, the hydroxyl value of the second base polymer may be from 0 to 100mgKOH/g, such as from 0 to 95mgKOH/g, from 0 to 90mgKOH/g, from 0 to 85mgKOH/g, from 0 to 80mgKOH/g, from 2 to 100mgKOH/g, from 2 to 95mgKOH/g, from 2 to 90mgKOH/g, from 2 to 85mgKOH/g, from 2 to 80mgKOH/g, from 5 to 100mgKOH/g, from 5 to 95mgKOH/g, from 5 to 90mgKOH/g, from 5 to 85mgKOH/g, from 5 to 80mgKOH/g, from 10 to 100mgKOH/g, from 10 to 95mgKOH/g, from 10 to 90mgKOH/g, from 10 to 85mgKOH/g, or from 10 to 80 mgKOH/g.

In certain embodiments, the second base polymer includes acid functional groups, such as carboxylic acid functional groups. The presence of acid functionality in the polymer can be quantified by the acid number of the polymer, i.e., the amount of potassium hydroxide required to neutralize one gram of polymer containing acid groups. In one embodiment, the second base polymer of the adhesive layer has an acid value of less than 100mgKOH/g, such as less than 95mgKOH/g, less than 90mgKOH/g, less than 85mgKOH/g, or less than 80 mgKOH/g. With respect to the lower limit, the acid value of the second base polymer can be greater than 0mgKOH/g, such as greater than 2mgKOH/g, greater than 5mgKOH/g, or greater than 10 mgKOH/g. In terms of ranges, the acid value of the second base polymer may be from 0 to 100mgKOH/g, such as from 0 to 95mgKOH/g, from 0 to 90mgKOH/g, from 0 to 85mgKOH/g, from 0 to 80mgKOH/g, from 2 to 100mgKOH/g, from 2 to 95mgKOH/g, from 2 to 90mgKOH/g, from 2 to 85mgKOH/g, from 2 to 80mgKOH/g, from 5 to 100mgKOH/g, from 5 to 95mgKOH/g, from 5 to 90mgKOH/g, from 5 to 85mgKOH/g, from 5 to 80mgKOH/g, from 10 to 100mgKOH/g, from 10 to 95mgKOH/g, from 10 to 90mgKOH/g, from 10 to 85mgKOH/g, or from 10 to 80 mgKOH/g.

In certain embodiments, the second base polymer has a glass transition temperature of-50 to 10 ℃, such as-50 to 8 ℃, -50 to 5 ℃, -50 to 2 ℃, -50 to 0 ℃, -48 to 10 ℃, -48 to 8 ℃, -48 to 5 ℃, -48 to 2 ℃, -48 to 0 ℃, -45 to 10 ℃, -45 to 8 ℃, -45 to 5 ℃, -45 to 2 ℃, -45 to 0 ℃, -42 to 10 ℃, -42 to 8 ℃, -42 to 5 ℃, -42 to 2 ℃, -42 to 0 ℃, -40 to 10 ℃, -40 to 8 ℃, -40 to 5 ℃, -40 to 2 ℃, or-40 to 0 ℃. With respect to the lower limit, the second base polymer may have a glass transition temperature greater than-50 ℃, such as greater than-48 ℃, greater than-45 ℃, greater than-42 ℃ or greater than-40 ℃. With respect to the upper limit, the glass transition temperature of the second base polymer may be less than 10 ℃, e.g., less than 8 ℃, less than 5 ℃, less than 2 ℃, or less than 0 ℃.

In one embodiment, the adhesive layer comprises the second base polymer in an amount of 50 to 100 wt.%, e.g., 55 to 100 wt.%, 60 to 100 wt.%, 65 to 100 wt.%, 50 to 95 wt.%, 55 to 95 wt.%, 60 to 95 wt.%, 65 to 95 wt.%, 50 to 90 wt.%, 55 to 90 wt.%, 60 to 90 wt.%, 65 to 90 wt.%, 50 to 85 wt.%, 55 to 85 wt.%, 60 to 85 wt.%, or 65 to 85 wt.%, based on the total weight of the adhesive layer. With respect to the lower limit, in certain embodiments of the flame retardant label, the adhesive layer may include greater than 50 wt.%, such as greater than 55 wt.%, greater than 60 wt.%, or greater than 65 wt.% of the second base polymer, based on the total weight of the adhesive layer. As an upper limit, in certain embodiments of the flame retardant label, the adhesive layer may include less than 100 wt.%, e.g., less than 95 wt.%, less than 90 wt.%, or less than 85 wt.% of the second base polymer, based on the total weight of the adhesive layer.

As mentioned above, the adhesive layer may also include a tackifier. In general, tackifiers are compounds that are used to increase the tack, e.g., viscosity, of an adhesive surface. The composition of the tackifier of the adhesive layer may vary widely so long as the features disclosed herein are met. In certain embodiments, the tackifier may comprise rosin, rosin derivatives, terpenes, modified terpenes, aliphatic, cycloaliphatic, or aromatic resins, hydrogenated hydrocarbon resins, terpene phenolic resins, or derivatives thereof, or combinations thereof. In some cases, the tackifier is a rosin resin, an AMS resin, or a coumarone resin. In other cases, the tackifier is a combination of a rosin resin and a terpene resin.

In one embodiment, the tackifier of the adhesive layer has an average softening point of less than 125 ℃, such as less than 120 ℃, less than 115 ℃, or less than 110 ℃. With respect to the lower limit, the tackifier may have an average softening point greater than 50 ℃, e.g., greater than 55 ℃, greater than 60 ℃, greater than 65 ℃, or greater than 75 ℃. In terms of ranges, the tackifier may have an average softening point of 50 to 125 ℃, e.g., 50 to 120 ℃, 50 to 115 ℃, 50 to 110 ℃, 55 to 125 ℃, 55 to 120 ℃, 55 to 115 ℃, 55 to 110 ℃, 60 to 125 ℃, 60 to 120 ℃, 60 to 115 ℃, 60 to 110 ℃, 65 to 125 ℃, 65 to 120 ℃, 65 to 115 ℃, 65 to 110 ℃, 75 to 125 ℃, 75 to 120 ℃, 75 to 115 ℃, or 75 to 110 ℃.

In one embodiment, the adhesive layer comprises the tackifier in the range of 5 to 60 wt.%, e.g., 5 to 55 wt.%, 5 to 50 wt.%, 5 to 40 wt.%, 8 to 60 wt.%, 8 to 55 wt.%, 8 to 50 wt.%, 8 to 40 wt.%, 10 to 60 wt.%, 10 to 55 wt.%, 10 to 50 wt.%, 10 to 40 wt.%, 12 to 60 wt.%, 12 to 55 wt.%, 12 to 50 wt.%, 12 to 40 wt.%, 15 to 60 wt.%, 15 to 55 wt.%, 15 to 50 wt.%, or 15 to 40 wt.%, based on the total weight of the adhesive layer. With respect to the lower limit, the adhesive layer may include greater than 5 wt.% tackifier, such as greater than 8 wt.%, greater than 10 wt.%, greater than 12 wt.%, or greater than 15 wt.%, based on the total weight of the adhesive layer. As an upper limit, the adhesive layer may include less than 60 wt.% tackifier, such as less than 60 wt.%, less than 55 wt.%, less than 50 wt.%, or less than 40 wt.%, based on the total weight of the adhesive layer.

The inventors have surprisingly and unexpectedly found that the relative amounts of tackifier and second base polymer affect the adhesive activity of the flame retardant label. In particular, maintaining a specific weight ratio of tackifier to second base polymer ensures that the adhesion properties of the flame retardant label are satisfactory despite the addition of flame retardant. In one embodiment, the weight ratio of tackifier to second base polymer in the adhesive layer is 1: 10 to 1.5: 1, such as 1: 5 to 1.5: 1, 3: 10 to 1.5: 1, 2: 5 to 1.5: 1, 1: 2 to 1.5: 1, 1: 10 to 1.4: 1, 1: 5 to 1.4: 1, 3: 10 to 1.4: 1, 2: 5 to 1.4: 1, 1: 2 to 1.4: 1, 1: 10 to 1.3: 1, 1: 5 to 1.3: 1, 3: 10 to 1.3: 1, 2: 5 to 1.3: 1, 1: 2 to 1.3: 1, 1: 10 to 1.2: 1, 1: 5 to 1.2: 1, 3: 10 to 1.2: 1, 2: 5 to 1.2: 1, 1: 2 to 1, 1: 2: 1, 1: 1 to 1.2: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1: 1, 1. For a lower limit, the weight ratio of tackifier to second base polymer may be greater than 1: 10, such as greater than 1: 5, greater than 3: 10, greater than 2: 5, or greater than 1: 2. For an upper limit, the weight ratio of tackifier to second base polymer may be less than 1.5: 1, e.g., less than 1.4: 1, less than 1.3: 1, less than 1.2: 1, or less than 1: 1.

As described above, the adhesive layer may further include a second crosslinking agent. Generally, the crosslinking agents differ in crosslinking agent density and reaction rate. The inventors have surprisingly found that selecting the second crosslinker based on these parameters beneficially affects the formation of channels in the adhesive layer, as described below. The composition of the second crosslinker can vary widely. For example, the second crosslinking agent may include isocyanate compounds, dialdehydes, metal chelates, metal alkoxides, metal salts, and mixtures thereof. In some cases, the adhesive layer includes an epoxy crosslinker.

In one embodiment, the adhesive layer comprises the second crosslinker in an amount of 0.1 to 5 wt.%, e.g., 0.1 to 4 wt.%, 0.1 to 3 wt.%, 0.1 to 2 wt.%, 0.5 to 5 wt.%, 0.5 to 4 wt.%, 0.5 to 3 wt.%, 0.5 to 2 wt.%, 1 to 5 wt.%, 1 to 4 wt.%, 1 to 3 wt.%, 1 to 2 wt.%, 1.2 to 5 wt.%, 1.2 to 4 wt.%, 1.2 to 3 wt.%, 1.2 to 2 wt.%, 1.5 to 5 wt.%, 1.5 to 4 wt.%, 1.5 to 3 wt.%, or 1.5 to 2 wt.%, based on the total weight of the coating. With respect to the lower limit, the adhesive layer may comprise greater than 0.1 wt.%, e.g., greater than 0.5 wt.%, greater than 1 wt.%, greater than 1.2 wt.%, or greater than 1.5 wt.%, based on the total weight of the coating. In terms of an upper limit, the adhesive layer may comprise less than 5 wt.%, e.g., less than 4 wt.%, less than 3 wt.%, or less than 2 wt.%, based on the total weight of the coating.

The inventors have surprisingly and unexpectedly found that the relative amounts of the second crosslinker and the second base polymer affect the adhesion activity of the flame retardant label. In particular, maintaining a specific weight ratio of the second crosslinker to the second base polymer ensures that the adhesion properties of the flame retardant label are satisfactory despite the addition of the flame retardant. In one embodiment, the weight ratio of the second crosslinker to the second base polymer in the adhesive layer is 1: 100 to 15: 100, such as 1.5: 100 to 15: 100, 2: 100 to 15: 100, 2.5: 100 to 15: 100, 3: 100 to 15: 100, 1: 100 to 12: 100, 1.5: 100 to 12: 100, 2: 100 to 12: 100, 2.5: 100 to 12: 100, 3: 100 to 12: 100, 1: 100 to 10: 100, 1.5: 100 to 10: 100, 2: 100 to 10: 100, 2.5: 100 to 10: 100, 3: 100 to 10: 100, 1: 100 to 8: 100, 1.5: 100 to 8: 100, 2: 100 to 8: 100, 2.5: 100 to 8: 100, 3: 100 to 8: 100, 1: 100 to 5: 100, 1.5: 100 to 5: 100, 2: 100 to 5: 100, or 3: 100 to 5: 100. With respect to the lower limit, the weight ratio of the second crosslinker to the second base polymer can be greater than 1: 100, e.g., greater than 1.5: 100, greater than 2: 100, greater than 2.5: 100, or greater than 3: 100. With respect to the upper limit, the weight ratio of the second crosslinker to the second base polymer can be less than 15: 100, e.g., less than 15: 100, less than 12: 100, less than 10: 100, less than 8: 100, or less than 5: 100.

The adhesive layer may further include a second flame retardant. There may be a large difference in the composition of the second flame retardant. In particular, any flame retardant suitable for use as the first flame retardant described above may be used as the second flame retardant, so long as the other characteristics of the flame retardant label discussed herein are met. The first flame retardant of the coating layer may be the same as or different from the second flame retardant used in the adhesive layer. In certain embodiments, the first flame retardant is different from the second flame retardant.

In one embodiment, the adhesive layer comprises the second flame retardant in an amount of 0.5 to 35 wt.%, e.g., 1 to 35 wt.%, 2 to 35 wt.%, 3 to 35 wt.%, 0.5 to 30 wt.%, 1 to 30 wt.%, 2 to 30 wt.%, 3 to 30 wt.%, 0.5 to 25 wt.%, 1 to 25 wt.%, 2 to 25 wt.%, 3 to 250 wt.%, 0.5 to 20 wt.%, 1 to 20 wt.%, 2 to 20 wt.%, or 3 to 20 wt.%, based on the total weight of the adhesive layer. With respect to the lower limit, in certain embodiments of the flame retardant label, the adhesive layer may comprise greater than 0.5 wt.%, e.g., greater than 1 wt.%, greater than 2 wt.%, or greater than 3 wt.%, based on the total weight of the adhesive layer, of the second flame retardant. As an upper limit, in certain embodiments of the flame retardant label, the adhesive layer may include less than 35 wt.%, e.g., less than 30 wt.%, less than 25 wt.%, or less than 20 wt.% of the second flame retardant.

In one embodiment, the coating weight of the adhesive layer is 5 to 50g/m²E.g. 5 to 45g/m²5 to 40g/m²5 to 35g/m²5 to 30g/m²8 to 50g/m²8 to 45g/m²8 to 40g/m²8 to 35g/m²8 to 30g/m²10 to 50g/m²10 to 45g/m²10 to 40g/m²10 to 35g/m²10 to 30g/m²12 to 50g/m²12 to 45g/m²12 to 40g/m²12 to 35g/m²12 to 30g/m²15 to 50g/m²15 to 45g/m²15 to 40g/m²15 to 35g/m²Or 15 to 30g/m². As a lower limit, the coating amount of the adhesive layer may be more than 5g/m²E.g. greater than 8g/m²Greater than 10g/m²More than 12g/m²Or more than 15g/m². In terms of upper limit, the coating amount of the adhesive layer may be less than 50g/m²E.g. less than 45g/m²Less than 40g/m²Less than 35g/m²Or less than 30g/m²。

Backing layer

According to certain embodiments, the flame retardant label may comprise a backing layer. The backing layer may be releasable. In certain embodiments, the backing layer can be positioned adjacent to the adhesive layer on a side of the adhesive layer opposite the film layer. In this regard, the backing layer may protect the adhesive layer before the flame retardant label is applied (or intended to be applied) to a substrate (e.g., an electrical device), such as during manufacturing, printing, shipping, storage, and other processes. Any material suitable for use in a release liner may be used. Typical and commercially available release liners that may be suitable for use in embodiments may include silicone-treated release papers or Films, such as those available from Loparex, including such as 1011, 22533 and 11404, CP Films and Akrosil^TMThe product of (1).

In certain embodiments, the backing layer comprises embossed plastic paper. In some cases, the backing layer can include glassine paper, kraft paper, and/or other paper products coated with a backing polymer. For example, the backing layer may comprise cellophane coated with polyethylene. In certain embodiments, the amount of the liner polymer applied ranges from 5 to 50g/m²E.g. 5 to 45g/m²5 to 40g/m²5 to 35g/m²5 to 30g/m²8 to 50g/m²8 to 45g/m²8 to 40g/m²8 to 35g/m²8 to 30g/m²10 to 50g/m²10 to 45g/m²10 to 40g/m²10 to 35g/m²10 to 30g/m²12 to 50g/m²12 to 45g/m²12 to 40g/m²12 to 35g/m²12 to 30g/m²15 to 50g/m²15 to 45g/m²15 to 40g/m²15 to 35g/m²Or 15 to 30g/m². With respect to the lower limit, the coating weight of the liner polymer may be more than 5g/m²E.g. greater than 8g/m²Greater than 10g/m²More than 12g/m²Or more than 15g/m². As an upper limit, the coating weight of the liner polymer may be less than 50g/m²E.g. ofLess than 45g/m²Less than 40g/m²Less than 35g/m²Or less than 30g/m²。

In one embodiment, the total coating weight of the backing layer is from 50 to 150g/m²E.g. 50 to 145g/m²50 to 140g/m²50 to 135g/m²50 to 130g/m²80 to 150g/m²80 to 145g/m²80 to 140g/m²80 to 135g/m²80 to 130g/m²100 to 150g/m²100 to 145g/m²100 to 140g/m²100 to 135g/m²100 to 130g/m²120 to 150g/m²120 to 145g/m²120 to 140g/m²120 to 135g/m²120 to 130g/m². In terms of the lower limit, the coating weight of the backing layer may be more than 50g/m²E.g. greater than 80g/m²More than 100g/m²More than 120g/m². In terms of upper limit, the coating weight of the backing layer may be less than 150g/m²E.g. less than 145g/m²Less than 140g/m²Less than 135g/m²Or less than 130g/m²。

In some embodiments, the liner layer has opposing top and bottom surfaces, wherein the bottom surface is the surface facing the substrate. The arrangement of the backing layer relative to the other layers can vary widely. In certain embodiments, the backing layer contacts the adhesive layer. In some cases, the top surface of the backing layer contacts the bottom surface of the adhesive layer. In these embodiments, the backing layer may be removed from the adhesive layer prior to application of the flame retardant label so that the bottom surface of the adhesive layer may be subsequently affixed to an electrical device to be labeled, such as a battery.

As noted above, in certain embodiments of the flame retardant label, the backing layer includes a spine. In some cases, the top surface of the backing layer includes ridges so that channels can be formed in the bottom surface of the adhesive layer. In embodiments where the top surface of the backing layer includes a ridge and contacts the bottom surface of the adhesive layer, the ridge of the backing layer remains embossed as a channel in the bottom surface of the adhesive layer when the backing layer is removed during application. These channels may provide for air venting during application of the label to the electrical device. As mentioned above, there may be large differences in the planar design or layout of these ridges.

The flame retardant label of the present disclosure meets flame retardant requirements under UL94 VTM standard (2016). UL94 is a standard for determining whether a material will extinguish or spread a flame after ignition of a specimen. Test procedures for evaluating flame retardant properties according to UL94 VTM are well known, for example, as described in http:// industries.u1.com/plastics-and-components/plastics/plastics-testing # UL 94. Typically, to evaluate the flame retardant performance of the labels disclosed herein, at least one set of five test specimens was tested. Each sample was burned for 3 seconds. The combustion source ("burner") was then removed, and the time from removal to combustion stop was recorded as T1. Subsequently, the sample was burned again for three minutes. The combustion source was removed again, and the time until the second combustion was stopped was recorded as T2. The VTM test typically measures the flame retardant performance of a set of five test specimens and the total flaming combustion time of each specimen; total flaming combustion time for all 5 specimens of any group; the glowing combustion time of each sample after the second burner flame application; whether glowing or flaming combustion of any specimen reaches the holding fixture; the cotton placed under the sample was observed and recorded for ignition by any of the test specimen's flame drops.

Table 1 shows the requirements for the VTM-0, VTM-1 or VTM standards.

TABLE 1 VTM-0, VTM-1 and VTM-2 Standard

Table 1: UL94 VTM standard

In certain embodiments, the flame retardant label has a flammability rating in accordance with the requirements of the UL94 VTM-2 standard. In other embodiments, the flame retardant label has a flammability rating in accordance with the requirements of the UL94 VTM-1 standard. In certain embodiments, the flame retardant label has a flammability rating in accordance with the requirements of the UL94 VTM-0 standard.

Characteristic features

The flame retardant labels of the present disclosure are substantially matte and substantially translucent. In certain embodiments, the flame retardant label is matte due to, for example, the presence of channels in the adhesive layer. The inventors have found that a synergistic combination of air evacuation channels and a particular composition of a particular layer, such as an adhesive layer, unexpectedly provides the desired haze characteristics of the label.

The translucency of a film, such as a flame retardant label, can be quantified by its haze value. The haze value describes the amount of light scattering that occurs as light passes through a sample of the film. In particular, the haze value represents the percentage of transmitted light that deviates from the incident beam by forward scattering when passing through the specimen. In one embodiment, the flame retardant label has a haze value of 5% to 80%, such as 5% to 75%, 5% to 65%, 5% to 60%, 10% to 80%, 10% to 75%, 10% to 65%, 10% to 60%, 15% to 80%, 15% to 75%, 15% to 65%, 15% to 60%, 20% to 80%, 20% to 75%, 20% to 65%, 20% to 60%, 25% to 80%, 25% to 75%, 25% to 65%, or 25% to 60%. With respect to the lower limit, the flame retardant label may have a haze value of greater than 5%, such as greater than 10%, greater than 15%, greater than 20%, or greater than 25%. In terms of an upper limit, the flame retardant label may have a haze value of less than 80%, such as less than 75%, less than 70%, less than 65%, or less than 60%.

Application method

The present disclosure also relates to methods of applying flame retardant labels to electrical devices. These methods include the steps of: (i) providing a flame retardant label comprising a coating layer, a film layer, and an adhesive layer, and (ii) attaching the flame retardant label to an electrical device. In some cases, the electrical device is a battery.

In certain embodiments, the flame retardant label may further comprise a backing layer, which may be in contact with the adhesive layer. In these embodiments, the method further comprises the step of removing the liner layer. By removing the backing layer, the adhesive layer can be exposed and then attached to the electrical device to be labeled. As described above, the backing layer can include a ridge, and the ridge can create a channel in the adhesive layer that remains when the backing layer is removed. These channels provide air venting during application of the label to the electronic device. For example, a user may release any air trapped under the flame retardant label by applying pressure to the outer surface of the flame retardant label, e.g., to the top surface of the coating. The entrained air may flow through a channel in the adhesive layer and be released from under the label.

Examples

The flame retardant label was prepared as follows. Each flame retardant label comprises, from top to bottom, a coating layer, a PET film layer, an adhesive layer, and a liner.

In all of the flame retardant labels prepared, the coating layer was formed of a polyester resin, a flame retardant including Exolit OP 935, an isocyanate crosslinking agent, a wetting agent, and MIBK and toluene as solvents. The coating has a thickness of about 10 μm. The formulation of the coating is shown in table 2.

The PET film layer has a thickness of about 25 μm.

Two formulations of the adhesive layer were prepared. Each adhesive layer is formed of a hydroxyl-substituted acrylic polymer resin, a tackifier, Exolit OP 935, an epoxy resin, and MIBK and toluene as a solvent. The coating weight of each adhesive layer is about 20-30 grams per square meter. The formulations of the adhesives are shown in table 3.

Flame retardant labels are prepared using one of two types of liner layers: polyethylene coated cellophane with ridges, or polyethylene coated cellophane without ridges.

Table 2: formulation of coating

Table 3: formulation of adhesive layer

The prepared flame retardant label was tested several times. These tests include visual inspection and rating the label appearance on a scale of 1-5, with a score of 5 being most preferred. These tests also measured haze values, 180 ° peel strength, and flame retardancy. The results of these tests are shown in table 4.

Table 4: test data for the flame retardant labels prepared

As shown in table 4, the labels prepared as disclosed herein exhibit an unexpected combination of performance characteristics. In particular, the particular layer composition, and in some cases the formation of air vent channels therein, provides excellent label appearance in addition to the preferred haze properties. In addition, the label has excellent peel strength and flame retardancy.

Detailed description of the preferred embodiments

The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

Embodiment 1: a flame retardant label comprising: a coating comprising a first base polymer, a first crosslinker, and a first flame retardant; a film layer; and an adhesive layer including a second base polymer, a second flame retardant, a tackifier, and a second crosslinking agent.

Embodiment 2: the flame retardant label of embodiment 1 wherein the adhesive layer is in contact with at least a portion of the film layer.

Embodiment 3: the flame retardant label according to any one of the preceding embodiments, wherein each of the coating layer, the film layer and the adhesive layer comprises a top surface and a bottom surface.

Embodiment 4: the flame retardant label according to any one of the preceding embodiments, wherein the adhesive layer defines a channel for air egress.

Embodiment 5: the flame resistant label of embodiment 4 wherein the channels are arranged as tessellated diamonds.

Embodiment 6: the flame retardant label according to any one of the preceding embodiments, wherein the flame retardant label has a haze value of 5 to 80.

Embodiment 7: the flame retardant label according to any one of the preceding embodiments, wherein the first base polymer comprises a polyester, a polyacrylate, or a combination thereof.

Embodiment 8: the flame retardant label according to any one of the preceding embodiments, wherein the coating comprises a polyester, a polyacrylate, or a combination thereof in an amount of 20 wt.% to 60 wt.%.

Embodiment 9: the flame retardant label according to any one of the preceding embodiments, wherein the first base polymer has a hydroxyl number of greater than 100 mgKOH/g.

Embodiment 10: the flame retardant label according to any one of the preceding embodiments, wherein the second base polymer comprises a polyester, a polyacrylate, or a combination thereof.

Embodiment 11: the flame retardant label according to any one of the preceding embodiments, wherein the second base polymer has a hydroxyl value of less than 100 mgKOH/g.

Embodiment 12: the flame retardant label according to any one of the preceding embodiments, wherein the second base polymer has an acid number of less than 100 mgKOH/g.

Embodiment 13: the flame retardant label according to any one of the preceding embodiments, wherein the second base polymer has a glass transition temperature of-50 ℃ to 10 ℃.

Embodiment 14: the flame retardant label according to any one of the preceding embodiments wherein the weight ratio of tackifier to second base polymer in the adhesive layer is from 1: 10 to 1.5: 1.

Embodiment 15: the flame retardant label according to any one of the preceding embodiments wherein the first crosslinking agent comprises an isocyanate.

Embodiment 16: the flame retardant label according to any one of the preceding embodiments, wherein the first flame retardant comprises an organic phosphinate.

Embodiment 17: the flame retardant label according to any one of the preceding embodiments, wherein the second flame retardant comprises an organic phosphinate.

Embodiment 18: the flame retardant label according to any one of the preceding embodiments wherein the tackifier in the adhesive layer has an average softening point of less than 125 ℃.

Embodiment 19: the flame retardant label according to any one of the preceding embodiments wherein the tackifier in the adhesive layer comprises rosin, terpene, or derivatives thereof, or combinations thereof.

Embodiment 20: the flame retardant label according to any one of the preceding embodiments, wherein the second crosslinking agent comprises an isocyanate, an epoxy, or a combination thereof.

Embodiment 21: the flame retardant label according to any one of the preceding embodiments, wherein the film layer comprises one or more resins selected from the group consisting of: polyesters, ABS, polyacrylates, Polycarbonates (PC), polyamides, Polyimides (PI), polyamideimides, polyacetals, polyphenylene oxides (PPO), polysulfones, Polyethersulfones (PES), polyphenylene sulfides, Polyetheretherketones (PEEK), polyetherimides (PEl), metallized polyethylene terephthalate (PET), polyvinyl fluoride (PVF), polyvinyl ethers (PEE), Fluorinated Ethylene Propylene (FEP), Polyurethanes (PUR), liquid crystal polymers (LCP, aromatic polyesters), polyvinylidene fluoride (PVDF), aramid fibers, DIALAMY (polymer alloys), polyethylene naphthalate (PEN), ethylene/tetrafluoroethylene (E/TFE), polyphenylsulfones (PPSU).

Embodiment 22: the flame retardant label according to any one of the preceding embodiments wherein the coating has a thickness of 1 to 30 μm.

Embodiment 23: the flame retardant label according to any one of the preceding embodiments wherein the film layer has a thickness of 10 to 60 μm.

Embodiment 24: the flame retardant label of any one of the previous embodiments, wherein the adhesive layer is applied at a weight of 5 to 50g/m²。

Embodiment 25: the flame retardant label according to any one of the preceding embodiments, wherein the flame retardant label has a flammability rating of VTM-0.

Embodiment 26: the flame retardant label according to any one of the preceding embodiments, wherein the bottom surface is the surface facing the object to be labeled and the top surface is the surface on the opposite side of the bottom surface.

Embodiment 27: the flame retardant label according to any one of the preceding embodiments, wherein the flame retardant label further comprises a liner layer in contact with the bottom surface of the adhesive layer.

Embodiment 28: the flame retardant label of embodiment 27 wherein the backing layer is applied at a weight of 50 to 150g/m²。

Embodiment 29: the flame retardant label of embodiment 27 or 28 wherein the liner layer comprises embossed plastic paper.

Embodiment 30: the flame retardant label according to any one of embodiments 27-29 wherein the liner layer comprises a glassine paper coated with a liner polymer.

Embodiment 31: the flame retardant label of embodiment 30 wherein the liner polymer is coated at a weight of 5 to 50g/m²。

Embodiment 32: the flame retardant label of any one of the previous embodiments, wherein the coating comprises a polyester in an amount of 25 wt.% to 40 wt.%; wherein the first base polymer has a hydroxyl number of greater than 100 mgKOH/g; wherein the second base polymer has a hydroxyl value of less than 80mgKOH/g and an acid value of less than 35 mgKOH/g; wherein the second base polymer has a glass transition temperature of-40 ℃ to 0 ℃; and wherein the flame retardant label has a flammability rating of VTM-0.

Embodiment 33: the flame retardant label according to any one of the preceding embodiments wherein the coating layer has a thickness of 5 to 15 μm, the film layer has a thickness of 20 to 30 μm, and the coating amount of the adhesive layer is 15 to 25g/m²。

Embodiment 34: the flame retardant label according to any one of the preceding embodiments, wherein the first crosslinking agent comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; the tackifier comprises terpene or rosin; and the second crosslinking agent comprises an isocyanate or an epoxy resin.

Embodiment 35: the flame retardant label according to any one of the preceding embodiments, wherein the first crosslinking agent comprises an isocyanate; the first flame retardant comprises an organic phosphinate; the second flame retardant comprises an organic phosphinate; the tackifier comprises terpene or rosin; the second crosslinking agent comprises isocyanate or epoxy resin; and wherein the flame retardant label has a flammability rating of VTM-0.

Embodiment 36: the flame retardant label according to any one of the preceding embodiments, wherein the flame retardant label is attached to a battery surface or battery packaging.

Embodiment 37: a method of labeling a battery comprising the steps of: providing a flame retardant label comprising: a coating comprising a first base polymer, an isocyanate crosslinker, and a first flame retardant; a film layer; and an adhesive layer comprising a second base polymer, a second flame retardant, a tackifier, and a second crosslinking agent; and attaching the flame retardant label to a battery surface or a battery package.