Pressure-sensitive adhesives and products with hyperbranched silsesquioxane cores and their preparation methods

Abstract

Pressure-sensitive adhesives comprising a hyperbranched silsesquioxane core polymer are described. Various methods for preparing the polymer and the pressure-sensitive adhesive are also described. Furthermore, a variety of articles, including tapes utilizing the pressure-sensitive adhesive, are described.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880059663.7, filed on July 24, 2018, entitled "Pressure-sensitive adhesive and article having a hyperbranched silsesquioxane core and preparation method thereof" (the corresponding PCT application was filed on July 24, 2018, and was filed with application number PCT / US2018 / 043401).

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 538,512, filed July 28, 2017, which is incorporated herein by reference in its entirety. Technical Field

[0004] This subject matter relates to a method for preparing pressure-sensitive adhesives with a novel architecture, represented by a hyperbranched shell surrounding a silsesquioxane core, the silsesquioxane core being chemically bonded to the hyperbranched shell. In many respects, precursor units acting as structural units undergo condensation reactions to form hyperbranched silsesquioxanes. In other respects, the architecture is controlled at both the core and shell levels. In still other respects, the chemical composition of the core is controlled by incorporating metal atoms into the core to prepare a hybrid metal core. In yet another respect, the hyperbranched architecture is controlled by using blends of various precursors. This subject matter also relates to pressure-sensitive adhesives formed by the described method. Furthermore, this subject matter relates to tapes and other articles using the pressure-sensitive adhesive. Background Technology

[0005] Although various compositions and practices are known for the preparation of (meth)acrylate pressure-sensitive adhesives, the basic components of conventional (meth)acrylate-based PSAs are generally composed of linear, uncrosslinked chains of polymers with defined moduli and glass transition temperatures. The term "linear" refers to the fact that the polymer's structural units (monomers) are linked end-to-end along the chain, resulting in a simple linear structure. A simplified diagram in Figure 1a illustrates the polymer structure of an uncrosslinked linear polymer chain. The linear polymer chains of PSAs are typically slightly crosslinked during subsequent processing, improving their cohesive strength at the expense of "peel" strength. It must be emphasized that crosslinking is detrimental to PSA performance. Nevertheless, crosslinking is undertaken to balance the physical properties of the PSA. Figure 2A and 2B The structure of the cross-linked polymer chain is shown.

[0006] Placing reactive groups at both ends of the chain or randomly distributing them on the backbone of the (meth)acrylate polymer chain is a common crosslinking technique practiced in the art. While crosslinking of linear polymers is a useful technique for many PSA applications, the performance range and processing capabilities are limited and have reached their limits. It must be noted that crosslinking is detrimental to the "tackiness" and "peel-off" properties of PSAs and should be avoided as much as possible. However, crosslinking is necessary to build shear strength, prevent adhesive leakage from the wound tape roll, and improve the die-cutting properties of the adhesive. But all of this comes at the expense of other properties. In the ideal PSA, the goal is to achieve high "shear" without sacrificing "peel-off" and "tackiness" properties. Therefore, methods that eliminate the need for crosslinking can broaden the performance window of PSAs.

[0007] Therefore, it is necessary to redesign the architecture of pressure-sensitive adhesives at the molecular level in order to expand the range of usable materials. In this regard, the inventors considered leveraging recent advances in polymer construction through a "designed architecture" strategy. It is important to note that controlled architecture is an active area of ​​research in polymer science, and it has already demonstrated benefits in many fields. Summary of the Invention

[0008] The difficulties and drawbacks associated with the previous methods are addressed in this topic as follows.

[0009] In one aspect, this subject provides a polymer comprising, substantially composed of, or consisting of hyperbranched polymers, said hyperbranched polymers comprising at least one pure silsesquioxane core and at least two polymer chains chemically bonded to each of said pure silsesquioxane cores. The pure silsesquioxane core may be a fully condensed core, a partially condensed core, or a combination of a fully condensed core and a partially condensed core. Each of said polymer chains of the hyperbranched polymer may consist of different polymer chains, the same polymer chains, or a combination of different polymer chains and the same polymer chains. Furthermore, the hyperbranched polymer and / or the polymer comprises at least about 50% by weight of (meth)acrylate monomers.

[0010] On the other hand, this subject matter provides a polymer comprising, substantially composed of, or composed of hyperbranched polymers, said hyperbranched polymers comprising at least one hybrid silsesquioxane core and at least two polymer chains chemically bonded to each of said hybrid silsesquioxane cores. The hybrid silsesquioxane core may be a fully condensed core, a partially condensed core, or a combination of a fully condensed core and a partially condensed core. Each of the polymer chains of the hyperbranched polymer may be composed of different polymer chains, the same polymer chains, or a combination of different polymer chains and the same polymer chains. Furthermore, the hyperbranched polymer and / or the polymer comprises at least about 50% by weight of (meth)acrylate monomers.

[0011] In another aspect, this subject provides a polymer comprising, substantially composed of, or composed of hyperbranched polymers, said hyperbranched polymers comprising (i) at least one pure silsesquioxane core and at least two polymer chains chemically bonded to each of said pure silsesquioxane cores and (ii) at least one hybrid silsesquioxane core and a combination of at least two polymer chains chemically bonded to each of said hybrid silsesquioxane cores. The pure silsesquioxane core and / or the hybrid silsesquioxane core may be a fully condensed core, a partially condensed core, or a combination of a fully condensed core and a partially condensed core. Each of the polymer chains of the hyperbranched polymer may be composed of different polymer chains, the same polymer chains, or a combination of different polymer chains and the same polymer chains. Furthermore, the hyperbranched polymer and / or the polymer comprises at least about 50% by weight of (meth)acrylate monomers.

[0012] On the other hand, the hybrid silsesquioxane core described in this article is a metal-silsesquioxane core.

[0013] In another aspect, this subject provides a polymer in which a portion of the discrete silsesquioxane core can be respectively as... Figure 14A and 14B The beaded chains or multidimensional network structures shown are connected together.

[0014] In another aspect, this subject provides a silsesquioxane core comprising Si atoms attached to at least one of three oxo groups and two oxo groups.

[0015] In another aspect, this subject provides a polymer comprising a polymer having the general formula [RSiO] 3 / 2 ] nThe silsesquioxane core, where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combinations thereof.

[0016] In another aspect, this subject provides a polymer comprising most polymers having the general formula [RSiO] 3 / 2 ] n The silsesquioxane core, where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combinations thereof.

[0017] In another aspect, this subject provides a polymer comprising [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x The silsesquioxane core, where "n" is a positive integer, "x" is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0018] In another aspect, this subject provides a polymer comprising most polymers having the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x The silsesquioxane core, where "n" is a positive integer, "x" is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0019] In another aspect, this subject matter provides a pressure-sensitive adhesive comprising the aforementioned polymer.

[0020] On the other hand, this subject provides an article comprising, substantially composed of, or composed of a pressure-sensitive adhesive, wherein the pressure-sensitive adhesive comprises the aforementioned polymer.

[0021] In another aspect, this subject matter provides a pressure-sensitive adhesive comprising a hyperbranched polymer, said hyperbranched polymer comprising at least one silsesquioxane core and at least two polymer chains chemically bonded to each of said silsesquioxane cores, wherein at least one of said hyperbranched polymer and said pressure-sensitive adhesive comprises at least about 50% by weight of (meth)acrylate monomer. Furthermore, the polymer is not crosslinked.

[0022] In another aspect, this subject provides a pressure-sensitive adhesive composed of a hyperbranched polymer having at least one silsesquioxane core and at least two polymer chains chemically bonded to each of the silsesquioxane cores, wherein at least one of the hyperbranched polymer and the pressure-sensitive adhesive comprises at least about 50% by weight of (meth)acrylate monomers. Furthermore, the polymer is not crosslinked.

[0023] In another aspect, this subject provides a method for forming a polymer comprising, substantially composed of, or composed of hyperbranched polymers, the hyperbranched polymer comprising at least one pure silsesquioxane core and at least two polymer chains chemically bonded to each of the pure silsesquioxane cores, or at least one hybrid silsesquioxane core and at least two polymer chains chemically bonded to each of the hybrid silsesquioxane cores, or (i) at least one pure silsesquioxane core and at least two polymer chains chemically bonded to each of the pure silsesquioxane cores and (ii) at least one hybrid silsesquioxane core and at least two polymer chains chemically bonded to each of the hybrid silsesquioxane cores. The pure silsesquioxane core and / or the hybrid silsesquioxane core may be a fully condensed core, a partially condensed core, or a combination of a fully condensed core and a partially condensed core. Each of the polymer chains of the hyperbranched polymer may be composed of different polymer chains, composed of the same polymer chains, or a combination of different polymer chains and composed of the same polymer chains. Furthermore, the hyperbranched polymer and / or pressure-sensitive adhesive contains at least about 50% by weight of (meth)acrylate monomers. The method includes providing a monomer with the formula R-Si(X). 3-a (Y) a The method involves a precursor step, wherein R is one of a non-hydrolyzable organic group, a non-hydrolyzable oligomer chain, and a non-hydrolyzable polymer chain, X is a hydrolyzable group, Y is an organic functional group, and the value of "a" is selected from the group consisting of 0, 1, 2, and combinations thereof. The method further includes subjecting the precursor to hydrolysis and condensation reactions, or condensation reactions only, to form a hyperbranched polymer.

[0024] In another aspect, this subject provides a pressure-sensitive adhesive comprising a polymer formed by the methods described above.

[0025] The pressure-sensitive adhesive described herein exhibits (i) a glass transition temperature (Tg) of approximately 10 °C to approximately -60 °C as determined by differential scanning calorimetry (DSC) and (ii) a 5 × 10⁻⁶ Tg at 25 °C and 1 radians / second as determined by dynamic mechanical analysis (DMA). 4 -6×10 6 dynes / cm 2 The platform shear modulus.

[0026] As will be appreciated, the subject matter described herein can have other and different aspects, and certain details therein can be modified in various respects, all without departing from the claimed subject matter. Therefore, the accompanying drawings and descriptions should be considered illustrative rather than restrictive.

[0027] Simple Explanation of the Diagram

[0028] Figure 1A This is a schematic diagram of an uncrosslinked linear polymer chain.

[0029] Figure 1B This is a schematic diagram of an uncrosslinked branched linear polymer chain.

[0030] Figure 2A This is a schematic diagram of a cross-linked linear polymer chain, where cross-linking occurs through groups randomly placed throughout the chain.

[0031] Figure 2B This is a schematic diagram of a cross-linked linear polymer chain, where cross-linking occurs through end groups.

[0032] Figure 3 This is a schematic diagram of a hyperbranched polymer structure.

[0033] Figure 4 This is a schematic diagram of a hyperbranched polymer with a pure silsesquioxane core.

[0034] Figure 5 This is a schematic diagram of a hyperbranched polymer with a hybrid metal-silsesquioxane core.

[0035] Figure 6 This is a schematic diagram of a fully condensed silsesquioxane unit with eight silicon atoms at its core.

[0036] Figure 7 This is a schematic diagram of the chemical structure of a fully condensed polymeric silsesquioxane unit.

[0037] Figures 8A to 8E The structure of a partially condensed sesquioxane is schematically shown.

[0038] Figure 9 This is a schematic diagram of a partially condensed silsesquioxane in a trapezoidal structure.

[0039] Figures 10A to 10E Various metal-silsesquioxane units are schematically shown.

[0040] Figure 11 The reaction between an organic alcohol and a hydrolyzable silane is illustrated schematically.

[0041] Figure 12It is a schematic diagram of an octahedral silsesquioxane core with eight arms or branches that are fully condensed.

[0042] Figure 13 This is a schematic diagram of a fully condensed polymeric metal-silsesquioxane core, where each silicon atom is attached to a polymer chain.

[0043] Figure 14A This is a schematic diagram of several hyperbranched silsesquioxane units connected in a beaded chain arrangement.

[0044] Figure 14B It is a schematic diagram of several hyperbranched silsesquioxane units arranged in a network.

[0045] Figure 15 This is a schematic diagram of a precursor unit containing a polymer chain linked to a silane group.

[0046] Figure 16 It is a schematic cross-sectional view of an article having a pressure-sensitive adhesive layer.

[0047] Figure 17 This is a schematic cross-sectional view of another product with a pressure-sensitive adhesive layer. Detailed Implementation

[0048] The subject of this invention is of particular interest to hyperbranched (meth)acrylic polymers based on silsesquioxane cores, which can be used in pressure-sensitive adhesives without the need for crosslinking.

[0049] The hyperbranched polymers discussed in this paper represent a new class of polymers. They possess unique properties that distinguish them from polymers belonging to the linear, branched-linear, and crosslinked types. Hyperbranched polymers typically exhibit an unusual topological structure, namely a "core-shell," characterized by very high local concentrations of chain ends in the outer layer (shell) of the macromolecule and very high local concentrations of branching points in the core. This topological structure enables unique properties. As a result, after reaching a certain degree of branching, the hydrodynamic volume stops increasing and exceeds a certain number-average molecular weight M. n Value (usually from M) n >10 4 (Initially), the growth of the fluid dynamic volume becomes significantly smaller than that of the same M. n The growth of linear macromolecules is a key characteristic of hyperbranched polymers. This tight packing and the abundance of free chain ends at the periphery represent the main structural and physical reasons for their unique properties. In some cases, hyperbranched polymers are amorphous, although their linear counterparts may be crystalline. The large number of end groups in hyperbranched polymers is believed to influence macromolecular properties such as glass transition temperature, solubility, dielectric properties, hydrophobicity, and thermal stability.

[0050] The characteristic of hyperbranched topology is that each macromolecule has a large number of chain ends, which is the basis of its special properties. For example... Figure 3 As shown, these special structures can be achieved as long as there is a method to covalently bundle one end of the polymer chains while leaving the other end of the chains free to hang. Two synthetic strategies for producing similar structures are: a) growing polymer chains outward from a central point in a multi-step synthesis (divergent approach), or b) growing individual polymer chains in the first step and then linking them at one end in the second step (convergent approach). Conventional PSA polymers typically designed for crosslinking will be unsuccessful in implementing strategies that produce hyperbranched topologies because such crosslinking would link the chains at two or more points instead of leaving them free to hang. Figure 3 The illustration shows a description of a hyperbranched polymer structure that is connected to a central core at one end, while the other end is free to move.

[0051] Surprisingly, it has been found that although silsesquioxane units themselves exhibit high modulus and high glass transition temperatures (these materials are typically “glassy” and “gritty”) and are not the preferred materials for PSAs, PSA properties can be exhibited through the appropriate design of novel hyperbranched polymers. Examples of PSAs based on hyperbranched silicon cores include... Figure 4 Those shown with pure silsesquioxane cores and Figure 5 Those shown have a hybrid metal-silsesquioxane core. Specifically, Figure 4 A hyperbranched structure with a silsesquioxane cage at its core and branchesing with soft polymer chains was described. Figure 4 This is a more general representation of hyperbranched polymers with a pure silsesquioxane core, while Figure 6 This refers to a discrete hyperbranched polymer having eight silicon atoms in a fully condensed cage. Actual polymers comprise one or more hyperbranched polymers, which can have cages of sizes such as 6, 8, 12, etc., and / or combinations of cages of different sizes. That is, an actual polymer can have six Si atoms in a first cage of a first hyperbranched polymer, in a... Figure 6 The diagram shows eight Si atoms in the second cage of the second hyperbranched polymer, twelve Si atoms in the third cage of the third hyperbranched polymer, and / or combinations of cages of different sizes. In other words, the first hyperbranched polymer can have six precursor units, and the second hyperbranched polymer can have eight precursor units, such as... Figure 6 As shown, the third hyperbranched polymer can have a combination of 12 precursor units and / or cages of different sizes. Since each precursor has one silicon atom, the number of silicon atoms will be the same as the number of condensation precursors.

[0052] Figure 5It shows a hyperbranched structure with a metal-silsesquioxane cage at its core and branches as polymer chains. Figure 5 This is a more general representation of hyperbranched polymers with hybrid silsesquioxane cores, while Figure 10A This refers to a discrete hyperbranched polymer containing seven silicon atoms and one M atom within a fully condensed cage. As mentioned above, actual polymers comprise one or more hyperbranched polymers, which can have cages of sizes such as 6, 8, 12, etc., and / or combinations of cages of different sizes. Figure 4 and Figure 10A In this context, R' represents the polymer chain of the hyperbranched polymer.

[0053] Furthermore, this strategy has been found to not only enable and / or simplify manufacturing possibilities but also provide significantly improved performance, while offering an excellent method for tuning adhesive properties. The formation of hyperbranched polymers with silsesquioxane cores is novel to the PSA field. Unbound by any theory, this novel structure is believed to offer optimal results in both areas. The silsesquioxane core contributes to high strength and heat resistance, while the hyperbranching provides tack and rapid adhesion. In addition to higher strength and heat resistance, the use of metal-silsesquioxane cores can produce polymers with altered and / or superior magnetic and optical properties (e.g., high refractive index). It must be noted that not all hyperbranched silsesquioxane-based structures achieve PSA formation, as the resulting composition's modulus and / or glass transition temperature may be outside the range of PSAs.

[0054] This subject provides a generally tacky PSA composition and an adhesive-coated sheet that has the necessary four-fold balance of adhesiveness, cohesion, viscoelasticity and glass transition temperature.

[0055] One objective of this topic is to provide a synthetic strategy for preparing PSA and tapes by assembling novel architectures represented by hyperbranched structures at the molecular level.

[0056] Another objective of this subject is to provide a method for preparing a soft hyperbranched shell of (meth)acrylate polymer chains surrounding a hard silsesquioxane core, said soft hyperbranched shell being usable as a pressure-sensitive adhesive.

[0057] Another objective of this subject is to produce (meth)acrylate brushes surrounding a hybrid metal-silsesquioxane core to form a pressure-sensitive adhesive material.

[0058] Another objective of this topic is to form novel controlled-structure acrylic pressure-sensitive adhesives with a silica core.

[0059] Another objective of this topic is to form a novel controlled architecture of acrylic PSA with a mixed silica-metal oxide core.

[0060] Another objective of this topic is to provide a synthetic strategy for synthesizing terminally functionalized acrylic precursors using free radical polymerization for hyperbranched pressure-sensitive adhesive systems.

[0061] Before focusing on the details and many aspects of this topic, it is helpful to consider several terms and their definitions as used in this article.

[0062] As used herein, the term "(meth)acrylate-based PSA" refers to a permanently adhesive polymer composition comprising any combination of acrylates, methacrylates, or such monomers, wherein the monomers (esters of acrylic acid or methacrylate) are polymerized or copolymerized with various comonomers containing polymerizable olefinic bonds. The polymer is formed via chain-growth polymerization. The (meth)acrylate polymer in the pressure-sensitive adhesive can be a homopolymer, i.e., composed of the same acrylic monomers forming the polymer chain. Alternatively, the acrylate polymer can be a copolymer, i.e., composed of two or more different monomers placed within the polymer chain. These polymers consist of linear or branched chains. These polymers are cast onto a film or foil carrier to form a PSA tape. In practice, most commonly, the polymer also undergoes a slight crosslinking reaction on the web to improve the internal strength of the polymer. Crosslinking is promoted by introducing reactive groups known in the art. Crosslinking of the polymer can be activated by any of the following triggering factors, such as heat, moisture, ultraviolet light, and / or electron beams.

[0063] The term “room temperature” as used in this article refers to a temperature in the range of approximately 15°C to approximately 25°C.

[0064] As used herein, the term "acrylic polymer" refers to a polymer formed in a polymer composition from monomers of acrylates and / or methacrylates, or any combination of these monomers, wherein said monomers are esters of acrylic or methacrylate containing polymerizable olefinic bonds. The term also includes other types of monomers having olefinic bonds that can be copolymerized with acrylate and methacrylate monomers.

[0065] The term "fully condensed" silsesquioxane core refers to a silsesquioxane core in which each silicon or metal atom covalently participates in the formation of three bonds using any combination of Si-O-Si and Si-OM bonds (e.g., Figure 6 , 7 10A, 10B, and 10E).

[0066] The term "partially condensed" silsesquioxane core refers to any combination of silsesquioxane cores in which some silicon or metal atoms are covalently bonded to two or fewer Si-O-Si and Si-OM bonds (e.g., Figures 8A to 8E 9, 10C and 10D).

[0067] The term "hyperbranched polymer" refers to a macromolecule composed of multiple polymer units emanating from a central core, such as... Figure 3 As shown in the diagram. Hyperbranched polymers are characterized by i) a core and ii) branches surrounding the core, also referred to herein as a “shell.” The core is characterized by its functionality, which is the number of chemical bonds that can be attached to the outside of the molecule. Topologically, these are synthetic dendritic macromolecules with dense branches and numerous end groups.

[0068] The term "pure silsesquioxane core" refers to a silsesquioxane core in which no silicon atom is replaced by another atom, such as... Figure 4 , 6 As shown in 8A-8E, 9, and 12. The terms "pure silsesquioxane core" and "silsesquioxane core" are used interchangeably in the description of this topic.

[0069] The term "hybridized silsesquioxane core" refers to a silsesquioxane core in which one or more silicon atoms are replaced by another atom, such as a metal or another Si atom. For example, as... Figure 5 , 10A As shown in -10D and 13, in a metal-silsesquioxane core, one or more silicon atoms in the core are replaced by metal atoms. The terms "metal-silsesquioxane core" and "hybrid metal-silsesquioxane core" are used interchangeably in the description of this topic.

[0070] The term "polymer brush" is generally characterized by attaching one end of a polymer chain to a substrate at a high density. The confined space then leads to strong chain extension and unusual properties of the system. The terms "hyperbranching" and "brush" are used interchangeably in the description of this topic.

[0071] The term "silane" refers to organosilicon compounds with the following typical molecular structure: R-(CH2). m -Si(X) 3-n R' n Where n = 0, 1, 2, and m = 0-20. Many combinations are possible, but silanes are characterized by the presence of a reactive group X. The X group is a hydrolyzable group, such as, but not limited to, methoxy, ethoxy, acetoxy, or oxime. The group R' is hydrogen or a hydrocarbon. The group R can be a hydrocarbon, heterohydrocarbon, polymeric group, or functional group, such as epoxy, vinyl, amino, methacryloyloxy, or thiocyanate.

[0072] The term "hydrolysis" refers to the reaction in which Si-X bonds break in the presence of water, or even just when water is adsorbed on a surface, to form silanol Si-OH groups.

[0073] The term "condensation" refers to the reaction in which two silanol groups condense, release water, and form a structure with very stable siloxane Si-O-Si bonds.

[0074] The term "precursor" refers to an acrylic or methacrylic acid polymer as defined above, which is end-capped at one end of the molecule with a single silane unit. In this subject matter, the term "precursor" refers to a starting molecule or macromolecular unit that can form a hyperbranched structure as described in detail herein through hydrolysis-condensation reaction or direct condensation self-assembly bypassing the hydrolysis step.

[0075] The term "crosslinking" or "crosslinking" refers to the process of forming chemical bonds that connect one polymer chain to another at more than one point along the chain. As shown in Figure 2, polymer chains are covalently pinned to other chains at more than one location. This contrasts sharply with hyperbranched polymers, such as... Figure 3 As shown, the chain is pinned at only one location.

[0076] Since the silsesquioxane unit forms the core of the hyperbranched structure of this subject, it is also beneficial to briefly consider its definition and related terminology. The silsesquioxane unit is a class of organosilicon compounds characterized by a silicon-to-oxygen ratio of 1.5, derived from the general formula [RSiO]. 3 / 2 ] n The structure is denoted as , where n is an even number and R is an organic or inorganic group, such as alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer, and combinations thereof. Many different substituents (R) can be attached to the Si center. Molecules with this structure are unusual because they feature an inorganic silicate core and an organic exterior. The organic group emanates from the central silicate core, leading to the formation of a hyperbranched structure. Furthermore, the benefits of hyperbranching and brush-like structures are inherent to these molecules. In some literature, this silsesquioxane structure is also referred to as an "organic-inorganic hybrid."

[0077] When a selected silane undergoes hydrolysis and condensation, it forms a silsesquioxane structure. Under certain reaction conditions, silanes can also bypass the hydrolysis step and undergo direct condensation. One such structure, belonging to the silsesquioxane family, is... Figure 6 The text indicates that in this specific instance, a polyhedral structure with eight silicon atoms is formed, namely (R-SiO₂). 1.58) to produce fully condensed silsesquioxane molecules. The silsesquioxane core imparts rigidity and thermal stability to the molecule. It must be noted that not all silanes react to spontaneously form silsesquioxane structures. The description of silsesquioxanes is given by P. Eisenberg, R. Erra-Balsells, Y. Ishikawa et al., “Cagelike Precursors of High-Molar-Mass Silsesquioxanes Formed by the Hydrolytic Condensation of Trialkoxysilanes,” Macromolecules, Vol. 33, No. 6, pp. 1940-1947, published in 2000. Figure 6 The chemical structure of a fully condensed silsesquioxane unit with eight silicon atoms at the core is shown.

[0078] Many stoichiometric silsesquioxane skeletons can be envisioned as having a synthetically useful functional group R. They are most often via a trifunctional organosilicon moiety, such as R-(CH2). m -Si(X)3, where m = 0-20, is prepared by hydrolysis and condensation reactions, where X is a hydrolyzable group, such as a halogen, acyloxy, ketooxime ester, or alkoxy group, and where R is a non-hydrolyzable organic group linked by a Si-C bond. The formation of a silsesquioxane core requires three such hydrolyzable groups on the silicon atom. Alkoxy groups are particularly preferred as the X group because of their mild hydrolytic properties and ease of handling.

[0079] Fully condensed silsesquioxane (R-SiO) 1.5 ) n The numbers n = 4, 6, 8, 10, and 12 are known in molecular form, corresponding to 4, 6, 8, 10, and 12 Si vertices, respectively. The cages are sometimes labeled T4, T6, T8, and T... 10 and T 12 (T = each Si center is chemically bonded to three oxo groups, and the subscripts indicate the number of Si atoms forming the cage). Furthermore, silsesquioxanes can also exist in polymeric forms. In polymeric forms, silsesquioxanes exhibit the following characteristics: Figure 7 The trapezoidal structure is shown. In all cage-like and polymeric forms with a fully condensed silsesquioxane core, each Si center is bonded to three oxo groups, which in turn are attached to other Si centers. The fourth group on the Si is typically a hydrocarbon, alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer, or combination thereof. Figure 7The chemical structure of a fully condensed polymeric silsesquioxane unit is shown. In cage-like and polymeric forms with a partially condensed silsesquioxane core, such as... Figures 8A-8D As shown, not all Si centers are bonded to three Si-O-Si groups; some Si centers are bonded to fewer than three Si-O-Si groups.

[0080] Silsesquioxane structures are typically formed by the hydrolysis of hydrolyzable silane molecules followed by condensation. Idealized synthesis can proceed through the following different steps:

[0081] a) Hydrolysis:

[0082]

[0083] b) Condensation:

[0084]

[0085] exist Figure 6 In this instance, n equals 8.

[0086] The structure of silsesquioxane skeletons is largely dependent on their preparation methods. This structure exhibits unique sensitivity to a combination of highly interdependent experimental factors, including product solubility, initial silane concentration, solvent properties and stability, temperature, pH, the amount of available free water, and the type of catalyst (acid or base) used to promote condensation. The reaction is typically catalyzed by Brønsted acids, Lewis acids, bases, and amines. Careful hydrolysis yields well-defined, fully condensed structures T4-R, T6-R, T8-R, T10-R, and T12-R. Note that polyhedral silsesquioxanes are also called spherical siloxanes because the polyhedral structure is topologically equivalent to a sphere.

[0087] In addition to the fully condensed structure, incompletely condensed structures containing Si-OH groups are also known, which have the general formula [R-SiO]. 3 / 2 ] n (H2O) (3n / 2)-x , where n is a positive integer, x represents the degree of contraction, and can take a positive integer value less than or equal to 3n / 2.

[0088] When the contraction process begins, it goes through the following two basic steps: the first step leads to incomplete contraction, and the second step leads to a fully contracted state.

[0089] a) Incompletely condensed silsesquioxanes:

[0090]

[0091] b) Fully condensed silsesquioxanes:

[0092]

[0093] These incompletely condensed materials can be a single, well-defined structure, a mixture of completely closed polyhedra, open polyhedra with dangling -OH groups, ladder structures, open structures with more -OH groups, linear structures, and various other possible combinations. Although not limited to these, Figures 8A-8E Illustrative examples of partially condensed silsesquioxane structures containing 8, 7, 6, and 5 silicon atoms are provided. Furthermore, to illustrate various possibilities, a structure with 6 silicon atoms is explained with two levels of condensation. These partially condensed silsesquioxanes are intermediates on the way to a fully condensed cage. Specifically, Figures 8A-8E It shows a structure with seven silicon atoms ( Figure 8A ), Figure 8B Six silicon atoms ( Figure 8B ), five silicon atoms ( Figure 8C ), six silicon atoms ( Figure 8D The partially condensed silsesquioxane core, and the ladder-shaped arrangement of eight silicon atoms in the silsesquioxane ( Figure 8E Various chemical structures of ).

[0094] In addition, polymerized silsesquioxanes have been reported. High molecular weight, easily processed polymerized silsesquioxanes are characterized by, for example, as... Figure 7 The trapezoidal structure shown is illustrated. Other condensed materials also employ a trapezoidal structure, including those composed of RSiO₂. 3 / 2 The two long chains composed of units are connected by Si-O-Si bonds at regular intervals, for example, Figure 9 As shown in the figure. Furthermore, the amorphous structure comprises RSiO₂ linked without any organized structural formation. 3 / 2 Unit. Specifically, Figure 9 The structure of a partially condensed polymeric silsesquioxane arranged in a ladder-like pattern is shown.

[0095] The silanols generated in situ within the incompletely condensed silsesquioxane intermediate are stable compounds, resulting in fairly good stability for silsesquioxanes with one or more hydroxyl groups. Simultaneously, the Si-OH group possesses sufficient reactivity to further react with metals and metalloids, thereby generating novel hybrid metal-silsesquioxanes. Incompletely condensed silsesquioxanes can combine with many metals, including Na. + Li + and Be 2+ , as well as metalloids and transition metals.

[0096] Another variation in the structure of silsesquioxanes is the formation of a hybrid core, in which one or more silicon atoms in the core are replaced by another atom. The material added to form the hybrid core is referred to herein as a "core modifier." It is important to note that this results in a change at the core level. Hybrid silsesquioxanes allow for a wide range of applications. Their chemistry has seen extensive development over the past 10-15 years. For example, by treating incomplete cages with metal halides in the presence of a catalyst, core stoichiometry [(RSi)] can be prepared. n (R'M) m O 1.5 ] n+m The synthesis yields clearly defined prismatic metal-silsesquioxane derivatives. The synthesis can be a sequential reaction or a one-pot reaction, wherein the metal component is added as a monolithic blend at the start of the hydrolysis step. Examples of such reactions are shown below.

[0097]

[0098] Figures 10A-10E Exemplary, but not limited to, structures are provided for the co-reaction of silsesquioxane polyols with various compounds of the RMX3 type, wherein R = alkyl, alkenyl, aryl, H; M = Al, Si, Ge, Sn, Ti, or Zr; and X = organic ligand, halogen, or alkoxide. This synthetic strategy yields a wide variety of hybrid silsesquioxane cores. Specifically, Figures 10A-10E Various chemical structures of the metal-silsesquioxane unit are shown; Figure 10A The diagram shows a fully condensed core with seven silicon atoms and one metal atom. Figure 10B The diagram shows a fully condensed core with five silicon atoms and three metal atoms. Figure 10C The diagram shows a partially condensed core with four silicon atoms and three metal atoms. Figure 10D The diagram shows a partially condensed core with four silicon atoms and three metal atoms, and... Figure 10E The diagram shows polymeric metal-sesquioxanes arranged in a ladder-like pattern.

[0099] In other respects, partially condensed silsesquioxanes can react with, for example, CrO3 to produce chromium silsesquioxanes. Partially condensed silsesquioxanes can react with, for example, (C3H7)3VO to produce vanadium silsesquioxanes. Partially condensed silsesquioxanes can react with, for example, FeCl3P(c-C6H) 11 The reaction 3 produces iron-containing silsesquioxanes. Partially condensed silsesquioxanes can undergo metal transfer with, for example, Mo to produce molybdenum-containing silsesquioxanes. Other metals known to be incorporated into the silsesquioxane structure include, but are not limited to, copper, rhodium, tungsten, osmium, and platinum.

[0100] In all respects, although many silsesquioxane structures may exist, the exact structure of a silsesquioxane is not important for the practice of this subject. In many cases, the composition will be a mixture of hyperbranched systems containing multiple silsesquioxane core structures.

[0101] Hydrolyzable silanes readily undergo another similar type of condensation reaction with organic alcohols present in the reaction medium. For example... Figure 11 As shown, Si-OC bonds are formed by the reaction of Si-X with the hydroxyl functional groups of the organic part. Figure 11 This demonstrates the direct condensation of silanes with hydroxyl groups. Although the mechanism of this reaction is not fully understood, it is generally believed to proceed via a one-step condensation. This method has been used to prepare silsesquioxanes with bulky R groups.

[0102] Using the aforementioned polymerization method for forming hyperbranched structures, and without being bound by any theory, it is believed that suitable acrylate precursors of the type described herein will form silsesquioxane-like cores hyperbranched with acrylate polymer chains during this reaction. This method of controlling polymer architecture produces pressure-sensitive adhesives with novel structures. Figure 12 An example of a fully closed polyhedral structure of a pressure-sensitive adhesive molecule as envisioned in this paper is shown. Figure 12 An octahedral, fully condensed silsesquioxane core is depicted, with polymer chains emanating from each silicon atom. This structure illustrates an eight-armed hyperbranched polymer molecule. Each arm represents a (meth)acrylate polymer chain. All chains emanate from the central silsesquioxane core. The structure of the silsesquioxane core can be any structure described herein. The silsesquioxane core can be fully condensed or partially condensed. Furthermore, the core can be cage-like or polymeric. Additionally, the core can be a mixture of any combination of any forms described herein.

[0103] In another instance of a hybrid core Figure 13 This paper describes the PSA molecule with a polymeric metal-silsesquioxane structure as envisioned in this paper. Figure 13 The fully condensed polymeric metal-silsesquioxane core is shown, with each silicon atom attached to a polymer chain.

[0104] Those skilled in the art will understand that integrating PSA and silsesquioxane into a single package is not intuitive. It will also be understood that this is a novel concept. To the best of our knowledge, the architecture of such a design and the benefits it yields are not described in the prior art. In fact, a hard silsesquioxane core is expected to have an adverse effect on the properties of PSA; however, surprisingly, this design provides unexpected benefits. This design simplifies the synthesis process while expanding the performance window of the resulting material, such as PSA. The hyperbranched silsesquioxane core is novel compared to the linear structural chains prevalent in conventional pressure-sensitive adhesive systems. This new architecture and synthesis strategy provides practitioners with better control over performance and process parameters. The properties of hyperbranched silsesquioxanes can be controlled through core-level modification of molecular structure, composition, and molecular weight (e.g., Example 11) or branch-level modification (e.g., Examples 1 to 7). In one aspect, as Figure 14A and 14B As shown, discrete silsesquioxane cores can be linked in bead chains or multidimensional network structures / arrangements. It is anticipated that by adding controlled amounts of diols, triols, or polyols, or any combination thereof, during the condensation step, each of the silsesquioxane cores of a portion of the hyperbranched polymer will be tandemly and covalently linked with another silsesquioxane core to form a bead chain structure. For example, in the case of diols, one hydroxyl group will react with one silsesquioxane core of the hyperbranched polymer, while another hydroxyl group will react with a silsesquioxane core of another hyperbranched polymer to form a link in the bead chain. The general structure of the diol, triol, or polyol is...

[0105]

[0106] Where R is a spacer group located between OH groups, and n is selected from the group consisting of 2, 3, 4, and combinations thereof. The spacer group is a small or large molecule containing two or more hydroxyl groups. For example... Figure 11 As shown, these hydroxyl groups directly participate in the condensation reaction with the hydrolyzable silane moiety to form Si-OC bonds. Examples of spacer groups can be, but are not limited to, polyether-based polyols, polyester-based polyols, and polycarbonate-based polyols. It is anticipated that the spacer groups can react with two or more adjacent silsesquioxane units to link them into a beaded configuration. The amount of polyol can be from about 0% to about 30% by weight of the PSA and / or the hyperbranched polymer, or from about 0% to about 20% by weight, or from about 0% to about 30% by weight. Excessive amounts will result in many tightly linked cores, which may negatively impact the performance of the PSA and should be avoided in some applications.

[0107] Further, it is anticipated that a controlled amount of hydrolyzable disilane will be added during the condensation step, and each of the silsesquioxane cores of a portion of the hyperbranched polymer will be covalently linked to one or more other silsesquioxane cores to form a multidimensional network structure. The general structure of the hydrolyzable disilane is...

[0108]

[0109] Where R is an organic group located between the two hydrolyzable silane moieties, X is a hydrolyzable group selected from the group consisting of halogens, acyloxy groups, ketooxime esters, alkoxy groups, and combinations thereof, Y is an organic functional group, and each "a" is independently selected from 0, 1, and 2. The amount of hydrolyzable disilane can be from about 0% to about 30% by weight of the PSA and / or the hyperbranched polymer, or from about 0% to about 20% by weight, or from about 0% to about 30% by weight. Excessive amounts will result in many tightly connected nuclei, which may negatively affect the performance of the PSA and should be avoided in some applications. Specifically, Figure 14A Several hyperbranched silsesquioxane units are shown, arranged in a “beaded chain” or in series. Figure 14B Several hyperbranched silsesquioxane units are shown, connected in a multidimensional network structure / arrangement, the most common being a two-dimensional network structure.

[0110] In many respects, the design of the precursor unit is beneficial for achieving the desired results. It should also be understood that, in order to achieve reasonable pressure-sensitive adhesive properties, each precursor unit should, in many respects, essentially have a single silane group, which should also be located at the terminal position. Not all acrylic precursors with silane groups are capable of forming hyperbranched topologies. Instead, most such systems are designed to promote undesirable crosslinking reactions. For example, more than one hydrolyzable silane group will pin polymer chains at multiple sites, resulting in a tightly crosslinked structure, which is generally detrimental to the function of the pressure-sensitive adhesive. Furthermore, the presence of hydrolyzable silane groups at positions other than the terminal position will spatially hinder the formation of a clearly hyperbranched silsesquioxane core relevant to this topic.

[0111] In implementing this subject, a precursor comprising an acrylate polymer with silane functional groups is subjected to hydrolysis and condensation in the presence of a catalyst to form a hyperbranched silsesquioxane core via a polymerization strategy. The silane functional groups are primarily represented by the general formula R-Si(X)3, where R is one of a non-hydrolyzable organic group, a non-hydrolyzable oligomer chain, or a non-hydrolyzable polymer chain, and X is as follows: Figure 15 The hydrolyzable groups shown. Figure 15Precursor units comprising polymer chains chemically linked to silane groups are shown. The polymer chains themselves may comprise homopolymers or copolymers. The polymer chains may be linear or branched. The hydrolysis / condensation reaction proceeds readily in the presence of trace amounts of moisture and heat. However, moisture may not be required in the presence of a catalyst or co-reactant.

[0112] In one aspect, a composition comprising a precursor, a core modifier, and a catalyst according to the subject matter can be dissolved in a θ solvent and cast onto a carrier substrate in the form of a film. The coated film is then subjected to a temperature range of about 20°C to about 50°C or an elevated temperature range of about 51°C to about 170°C to evaporate the solvent while undergoing condensation, thereby forming a hyperbranched silsesquioxane core.

[0113] On the other hand, the composition comprising the precursor, core modifier, and catalyst according to this subject matter can be heated to facilitate solvent-free formulation and dispensing. The formulation is applied in film form onto a carrier substrate. The coated film is subjected to a condensation reaction in a temperature range of about 20°C to about 50°C or an elevated temperature range of about 51°C to about 170°C to form a hyperbranched hybrid silsesquioxane core.

[0114] Furthermore, in this precursor, the silane functional group is chemically bonded to the acrylate polymer chain via spacer groups. In many respects, to ensure the formation of a silsesquioxane core, the reactive silane group cannot contain more than one silicon atom. In some respects, to ensure a silsesquioxane core, each precursor molecule cannot have more than one silane group. In some respects, to ensure a silsesquioxane core, the silane functional group must contain at least two or three hydrolyzable X groups, more preferably three groups.

[0115] Several chemicals capable of hydrolyzing the X group are available and can be used in this context. However, alkoxy groups are preferred given their mild reactivity and availability. Precursors having the following hydrolyzable moiety on a silane are preferred:

[0116] [Polymer]–CH2-(CH2) n -CH2Si(OCH3)3

[0117] [Polymer]–CH2-(CH2) n -CH2Si(OCH3)2(CH3)

[0118] [Polymer]–CH2-(CH2) n -CH2Si(OC2H5)3

[0119] [Polymer]–CH2-(CH2) n -CH2Si(OC2H5)2(CH3)

[0120] [Polymer]–CH2-(CH2) n -CH2Si(OC3H7)3

[0121] [Polymer]–CH2-(CH2) n -CH2Si(OC3H7)(CH3)

[0122] Where n is an integer from 0 to 18. The trialkoxysilyl groups found in these compounds hydrolyze and condense under appropriate conditions to form silsesquioxane structures, thereby forming the core of the hyperbranched structure.

[0123] The number-average molecular weight of the precursors is typically from about 2,000 to about 300,000 g / mol, preferably from 10,000 to 50,000 g / mol. The number-average molecular weight of the pressure-sensitive adhesive is typically from about 20,000 to about 1,000,000 g / mol, or from about 30,000 to about 500,000 g / mol, or from about 50,000 to about 200,000 g / mol. However, it should be understood that the subject matter is by no means limited to these molecular weights. To ensure that the hyperbranched silsesquioxanes derived therefrom exhibit pressure-sensitive adhesive properties, the chemical composition of the precursors is selected such that the final total hyperbranched silsesquioxane conforms to the rules of the Dahlquist standard known in the art and the glass transition temperature requirements for pressure-sensitive materials. According to the standard later known as the Dahlquist standard, for use as a pressure-sensitive adhesive, the formulation must have a molecular weight of 5 × 10⁻⁶ at 25°C and 1 radians / second, as determined by dynamic mechanical analysis. 4 -6×10 6 dynes / cm 2 The plateau shear modulus. At 25℃, the plateau shear modulus is greater than 1×10⁻⁶. 7 dynes / cm 2 The material is too hard at room temperature to exhibit tackiness, making it unsuitable for use as a pressure-sensitive adhesive. Its plateau shear modulus at 25°C is less than 1×10⁻⁶. 4 dynes / cm 2 The materials lack sufficient cohesive strength to be used as pressure-sensitive adhesives. Representative and non-limiting examples of the range of glass transition temperatures (Tg) of the pressure-sensitive adhesives of this subject, as measured by DSC, are about 10°C to about -60°C, or about 0°C to about -40°C, and / or about -10°C to about -40°C.

[0124] An attractive feature of this topic is that it allows for the generation of various hyperbranched structures by altering the composition of the polymer chains. The polymer chains can comprise polymer chains with different compositions, polymer chains with the same composition, and / or combinations of polymer chains with different compositions and polymer chains with the same composition. Polymer chains with different compositions include polymer chains of different lengths, sizes, chemical structures (linear, branched), molecular weights, and / or monomer units (polymers). Polymer chains with the same composition include polymer chains of substantially the same length, size, chemical structure (linear, branched), molecular weight, and / or monomer units (homopolymers). Furthermore, hyperbranched structures of mixed polymer chains can be achieved by condensing two or more precursors with different compositions. Examples of polymer chains with different compositions anchored to a core can produce amphiphilic silsesquioxanes with various ratios of hydrophilic and hydrophobic polymer chains. These systems are particularly interesting due to their intriguing phase behavior. Another example of forming polymer chains with different compositions is depicted in... Figure 11 middle. Figure 11 This demonstrates how to prepare silsesquioxanes with bulky R groups when hydrolyzable silanes readily undergo a one-step condensation reaction with organic alcohols. Two distinct polymer chains are bonded to the silsesquioxane core via Si-OC bonds: the precursor polymer chain and the organic alcohol polymer chain.

[0125] Furthermore, it is important to note that modifications can also be made at the silsesquioxane core level to prepare designed hybrid metal-silsesquioxane cores by combining hydrolyzable metals and metalloids with precursors in hydrolysis-condensation chemistry. Silsesquioxanes readily co-react with various core-modifying compounds of the types MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, where R = alkyl, alkenyl, aryl, or H; M = Al, Si, Ge, Sn, Ti, or Zr; and X = organic monodentate ligands, organic bidentate ligands, organic tripentate ligands, organic amphipathic ligands, halogens, or alkoxides. This simple synthetic method has short steps, high yields, and can produce materials with a wide range of properties.

[0126] In addition, other types of co-reactants used for core-level modification include M(X)4 and M(X). a (Z) b Where M is as described above, X is a hydrolyzable group, a is preferably 2, b is preferably 2, and Z is of the general formula AC(O)-(R'). nOrganic ligands of -C(O)-B, wherein R' is a hydrocarbon group, A and B are independently organic groups, and n is 0-10. The co-reactants are not particularly limited, but particularly include transition metal chelates; titanates, such as tetrabutyl titanate and tetraisopropyl titanate; organotin compounds and their carboxylic acid metal salts, such as dibutyltin dilaurate, dibutyltin diacetylacetonate, dibutyltin maleate, dibutyltin diacetate, and dimethoxydibutyltin; organoaluminum compounds, such as aluminum triacetylacetonate, aluminum triacetate (ethyl acetoacetate), and aluminum diisopropoxyacetate; and organozirconium compounds, such as zirconium tetraacetylacetonate, zirconium tetraisopropoxide, and zirconium tetrabutoxide. Examples of suitable compounds are provided by Dorfketal under the trade name. For example 9000 AA and GBA for sale. 9000 has the formula Ti(isopropoxy)4. Illustrative examples of suitable ligands are acetylacetonates, ethyl acetoacetate, ethylene glycol ethers, alkanolamines, and / or triethanolamine. Other metal chelates can be compounds prepared by coordinating multivalent metals such as Al, Fe, Zn, Sn, Sb, Mg, and V with suitable ligands such as acetylacetonates or ethyl acetylacetonate.

[0127] The molar ratio of metal content M to silicon content in the hybrid metal-silsesquioxane is preferably no greater than 30:1. More preferably, the molar percentage is no greater than 20:1. As an illustrative example, and without limitation, a novel hybrid titanium oxide / silsesquioxane core is synthesized by hydrolytic co-condensation of alkoxytitanium [Ti(OR')4R' = ethyl, isopropyl, butyl, and acetylacetonate compounds] with a precursor containing a trimethoxysilane. The co-condensation of titanium compounds is an easily carried out reaction that produces titanium dioxide-silica mixed oxides over a wide range of feed ratios.

[0128] In addition, core-level modification can also be achieved through silicon-containing co-reactants. The general formula for silicon-containing co-reactants is R”. 4-q Si(OR # ) q Where "R" represents a functional or non-functional hydrocarbon group, R #The symbol represents methyl, ethyl, or isopropyl, and the value of q is 2 or 3. Non-limiting examples of effective silicon compounds are propyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, decyltrimethoxysilane, 3-aminopropyltrimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldipropoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxydimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropyltrimeth ... γ-methyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-methacryloxymethyltriethoxysilane, (methacryloxymethyl)methyldimethoxysilane, (methacryloxymethyl)methyldiethoxysilane, γ-methacryloxypropyltriacetoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxymethyldiethoxysilane, γ-acryloxypropyltripropoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, etc.

[0129] In addition, tetraalkoxysilane Si(OR) # )4, for example, found in tetraethoxysilanes and tetramethoxysilanes, are other types of co-reactants used for core modification, in which R # This indicates methyl, ethyl, or isopropyl. Under appropriate conditions, these substances hydrolyze and condense to form a glassy gel structure. Co-condensation of tetraethoxysilane (TEOS) with its precursor is a convenient synthetic method for further modulating the structure of novel silsesquioxanes, such as altering solubility, rigidity, modulus, glass transition temperature, and refractive index.

[0130] Film-forming properties can be tuned by altering the composition of the precursor and core modifier feedstocks. This novel synthetic strategy provides a method for preparing designed pressure-sensitive adhesives, enabling practitioners in the field to adjust performance properties over a wide range.

[0131] Furthermore, regarding the polymer chain of the precursor, the polymer chain itself consists of acrylate and / or methacrylate monomers linked together to form straight-chain and / or branched homopolymers and / or copolymers. In many aspects, the pressure-sensitive adhesive and / or hyperbranched polymer contains at least about 50% or a majority of (meth)acrylate monomers, segments, and / or branches. A majority is defined as greater than about 50% by weight of PSA and / or hyperbranched polymer, about 57% by weight of PSA and / or hyperbranched polymer, greater than about 57% by weight of PSA and / or hyperbranched polymer, about 50% by weight to about 99.99% by weight, or about 60% by weight to about 99.99% by weight, or about 70% by weight to about 99.99% by weight of PSA and / or hyperbranched polymer. The monomers suitable for use in the precursors include C1 to about C20 alkyl, aryl, or cyclic acrylates, and may include, but are not limited to, the following: methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, benzyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, propylheptyl acrylate, isooctyl acrylate, n-dodecyl acrylate, n-decyl acrylate, isodecanyl acrylate, isostearyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, cyclohexyl acrylate, 4-tert-butylcyclohexyl acrylate, and functional derivatives of these acrylates, such as 2-hydroxyethyl acrylate, 2-chloroethyl acrylate, etc. Methacrylate monomers include C1 to about C20 alkyl, aryl or cyclic methacrylates, such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, isobornyl methacrylate, and functional derivatives of these methacrylates, such as 2-hydroxyethyl methacrylate, 2-chloroethyl methacrylate, etc.

[0132] Furthermore, the acrylate monomer can be copolymerized with other comonomers having reactive functional groups, such as acrylonitrile, acrylamide, methacrylamide, vinyl ester, vinyl ether, vinylamide, vinyl ketone, styrene, halogen-containing groups, ionic groups, acid-containing groups, base-containing groups, olefinic groups, silyl groups, epoxy groups, hydroxyl groups, anhydride groups, and mixtures of two or more of these groups. Silicyl, carboxyl, carbonyl, carbonate, isocyanate, amino, amide, imide, mercapto, and acetoacetyl groups are also contemplated, which can be combined in any combination and / or with one or more of the aforementioned groups.

[0133] Furthermore, acrylate monomers can be copolymerized with comonomers containing acrylamide groups. These can include acrylamides and their derivatives, including their N-substituted alkyl and aryl derivatives. These include N-methylacrylamide, N,N-dimethylacrylamide, tert-octylacrylamide, N-aminoethyl acrylate, N-aminoethyl methacrylate, etc.

[0134] Other examples of comonomers include vinyl ester groups, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl tert-carbonate, vinyl isobutyrate, etc.

[0135] Other examples of comonomers include vinyl ether groups, such as vinyl ethers having one to about eight carbon atoms, including ethyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, etc.

[0136] Other examples of comonomers include those containing acid groups, such as unsaturated carboxylic acids containing 3 to about 20 carbon atoms. Preferred groups include acrylic acid, methacrylic acid, vinyl sulfonic acid, itaconic acid, β-carboxyethyl acrylate, mono-2-acryloyloxypropyl succinate, etc.

[0137] Other examples of comonomers include epoxy groups, such as glycidyl methacrylate and glycidyl acrylate.

[0138] Other examples of comonomers include hydroxyl groups, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyisopropyl acrylate, hydroxyisopropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, etc.

[0139] In one respect, acrylic acid precursors can be formed using macromonomers (also known as macromers). Macromonomers can be represented by the following general formula:

[0140] X-(Y) n -Z

[0141] Where X is a vinyl group that can copolymerize with other monomers present in the precursor composition; Y is a divalent linker group, where n can be 0 or 1; Z is a monovalent polymer moiety, whose T g Above 20°C and with a weight-average molecular weight of about 2,000 to about 30,000.

[0142] Various polymerization techniques can be used to prepare precursors, including controlled polymerization techniques such as atom transfer radical polymerization (ATRP); reversible addition / fragmentation chain transfer polymerization (RAFT); and, in recent years, nitride-mediated polymerization (NMP) or stable radical polymerization (SFRP). In addition, other techniques have emerged from the development of novel catalysts and initiation systems. While these methods can be used to prepare desired precursors, they are generally found to be cumbersome, multi-step procedures. However, it has been unexpectedly found that the polymerization of acrylate and / or methacrylate monomers in the presence of a radical initiator and a chain transfer agent (CTA) with a silane at a specific molar ratio of initiator to CTA has successfully produced the desired precursor architecture in a single step, thus greatly simplifying the process.

[0143] Various free radical initiators are known and can potentially be incorporated into the compositions of this subject. A general class of free radical initiators belongs to the categories of ketone peroxides, diacyl peroxides, dialkyl peroxides, peroxy esters, peroxy ketals, peroxy dicarbonates, peroxy monocarbonates, and diazo compounds. Each of these compounds acts as a thermal initiator by absorbing heat energy transferred in the form of convection, conduction, or radiation. Another general class of free radical initiators belongs to the categories of α-hydroxyalkylphenyl ketones, α-aminoalkylphenyl ketones, benzyl ketals, phenoxyin ethers, α-dialkoxyacetophenones, and acylphosphine oxides. Each of these compounds acts as a photoinitiator by absorbing energy in the UV / visible region of the electromagnetic spectrum. Initiators belonging to both of these classes are particularly suitable for the synthesis of precursors, provided that each free radical fragment formed in the initiation step has the following general structure:

[0144]

[0145] In these structures, R represents a hydrocarbon segment. It is important to note that in many aspects of the synthetic strategies employed in this subject, each radical segment formed upon initiation preferably carries a hydroxyl group or a hydrolyzable silane group. Some examples of commercially available initiators that conform to the desired structure are 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis[1-(4-hydroxyphenyl)ethane], bis(2-hydroxyethyl)peroxide, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, but are not limited thereto.

[0146] Useful chain transfer agents include a variety of thiol-based compounds. In many respects, the presence of a hydrolyzable silane moiety on the chain transfer agent is a fundamental part of the synthetic strategy for preparing precursors. The general structure of a chain transfer agent is:

[0147]

[0148] Where R is the organic linking group located between the thiol and the hydrolyzable silane moiety, Y is the organic functional group, and the value of "a" is selected from the group consisting of 0, 1, 2, and combinations thereof. In one aspect, the value of "a" is 0 or 1, more preferably, the value of "a" is 0. In some aspects, in order to obtain the desired precursor structure, it is required that each molecule of the chain transfer agent has a single thiol group and a single silane group. Examples of thiol-containing silanes include mercaptoalkyltrialkoxysilanes, such as mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, β-mercaptoethyltrimethoxysilane, β-mercaptoethyltriethoxysilane, β-mercaptoethyltripropoxysilane, β-mercaptoethyltriisopropoxysilane, β-mercaptoethyltributoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltripropoxysilane, γ-mercaptopropyltriisopropoxysilane, and γ-mercaptopropyltributoxysilane; (mercaptoalkyl)alkyldianes Oxyktosilanes, such as β-mercaptoethylmethyldimethoxysilane, β-mercaptoethylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropylmethyldipropoxysilane, β-mercaptopropylmethyldiisopropoxysilane, γ-mercaptopropylmethyldibutoxysilane, γ-mercaptopropylethyldimethoxysilane, γ-mercaptopropylethyldiethoxysilane, γ-mercaptopropylethyldipropoxysilane, γ-mercaptopropylethyldiisopropoxysilane, and γ-mercaptopropylethyldibutoxysilane.

[0149] Some of these commercially available chain transfer agents are listed below, but are not limited to:

[0150]

[0151] While not wishing to be bound by any particular theory, it is believed that in many aspects of this subject, a very small amount of initiator must be used relative to the chain transfer agent specified herein to initiate the polymerization reaction. Under these conditions, after polymerization is initiated, the chain transfer agent immediately takes over, thereby terminating the growing chain, but cycling by generating new sulfur-centered radicals, which can be used for further and very efficient initiation to start the next chain. It has been found that by keeping the molar ratio of initiator to chain transfer agent very low, the vast majority of polymer chains are actually initiated by the chain transfer agent. Since the chain transfer agents used herein contain silane moieties, each chain initiated by the chain transfer agent also contains terminal silane groups.

[0152] In many respects, successful strategies utilize the chain transfer agent in combination with the radical initiator. The molar ratio of chain transfer agent to initiator is a crucial consideration in synthesizing the desired precursor architecture. By controlling the ratio of initiator to chain transfer agent, the ratio of polymer chains with terminal hydroxyl groups to silane groups can be controlled relatively easily. A higher ratio will ensure that more chains have terminal silane groups. However, a higher ratio will also reduce the molecular weight of the precursor. Not all combinations of the two yield favorable results. In many respects, the molar ratio of chain transfer agent to initiator can range from about 200:1 to about 1:2. This combination ensures that virtually all polymer chains have terminal hydroxyl or terminal silane groups.

[0153] The precursor can be synthesized in a solvent medium or in a solvent-free (bulk) synthesis. At a minimum, the monomer, initiator, and chain transfer agent are dissolved in an inert θ solvent and polymerized to form the precursor. Alternatively, the monomer, initiator, and chain transfer agent are polymerized in the absence of a solvent to form the precursor.

[0154] The synthesis of precursors can be initiated via a free radical mechanism through thermal or photochemical means, or any combination of both. The binder and / or precursor compositions of this subject matter contain free radical initiators, particularly photochemically activated initiators. In other respects, photochemical activation can be replaced by thermally activated initiators. However, it should be understood that this subject matter includes the use of virtually any type of initiator, and is not limited to α-cleavage or hydrogen abstraction types. For example, many initiators are known to decompose or split into free radicals upon exposure to heat or light, more particularly UV radiation.

[0155] Hyperbranched pressure-sensitive adhesive compositions may, in addition to precursors, contain oligomers having at least one crosslinkable functional group. The oligomers are typically liquid at room temperature (approximately 25°C). Examples of useful oligomers include those whose backbone comprises polyethers, polyisobutylene, amorphous polyalphaolefins, polybutadiene, polyisoprene, polydimethylsiloxane, polyalkyloxazoline, polyesters, poly(meth)acrylates, polyurethanes, and mixtures thereof. The polyether backbone may include, for example, polypropylene oxide, polyethylene oxide, and polytetramethylene ether glycol. The poly(meth)acrylate backbone may include C1-C14... 30(Meth)acrylates, which may or may not contain modified monomers. One or more reactive functional groups are attached to the oligomer backbone. Reactive functional groups may include silyl, hydroxyl, carboxyl, isocyanate, vinyl, (meth)acryloyl, epoxy, amino, mercapto, and acetoacetyl groups. The functional groups selected for the oligomer can react with the corresponding groups on the hyperbranched polymer. The specific functional groups used can be determined by those skilled in the art. For example, amino groups will react with isocyanate, epoxy, and acetoacetyl groups; isocyanate groups will crosslink with carboxyl, amino, and hydroxyl groups; (meth)acryloyl groups will crosslink with amino and acetoacetyl groups; and epoxy groups will crosslink with amino, carboxyl, and hydroxyl groups, etc.

[0156] Optionally, the tackifier can be combined with the precursor of the present invention. The tackifier is substantially compatible with the precursor. As used herein, the term "substantially compatible" means that when the tackifier and precursor are combined, the resulting combination is substantially transparent, rather than opaque, in dry film form during normal visual inspection. A variety of tackifiers can be used to enhance the tack and release properties of adhesives. These include rosin and rosin derivatives, including resinous materials naturally present in the oily resins of pine trees, and their derivatives, including rosin esters, modified rosin such as fractionated, hydrogenated, dehydrogenated, and polymerized rosin, modified rosin esters, etc.

[0157] Terpene resins, which are of formula C, can also be used. 10 H 16 Hydrocarbons, found in most plant essential oils and oleoresins; phenol-modified terpene resins, such as α-pinene, β-pinene, dipentene, limonene, geraniol, borneol, camphene, etc. Various aliphatic hydrocarbon resins can also be used, such as Escorez 1304 manufactured by Exxon Chemical Co., and aromatic hydrocarbon resins based on C9, C5, dicyclopentadiene, coumarone, indene, styrene, substituted styrene, and styrene derivatives.

[0158] Hydrogenated and partially hydrogenated resins can be used, such as Regalrez 1018, Regalrez 1033, Regalrez 1078, Regalrez 1094, Regalrez 1126, Regalrez 3102, Regalrez 6108, etc., manufactured by Eastman Chemical Company. For this subject matter, various terpene phenolic resins of the SP560 and SP553 types manufactured and sold by SI Group Inc., YSPolyster UH115 manufactured and sold by Yasuhara Chemical Co., Ltd., and Sylvares TP 2040 manufactured and sold by Kraton Corporation are particularly useful tackifiers. Various mixed aliphatic and aromatic resins can be used, such as Zonatac NG 98 manufactured and sold by Kraton Corporation.

[0159] While the aforementioned resins can be used to tackify precursor / oligomer blends of this subject matter, the specific tackifying resin and / or amount selected for a given formulation may depend on the chemical properties of the polymer system being tackified. Many resins known in the art for tackling acrylic-based pressure-sensitive adhesives can be effectively used in the practice of this subject matter, but the scope of this subject matter is not limited to these resins alone. Resins described in *Satas, Handbook of Pressure Sensitive Adhesive Technology*, Von Nostrand Reinhold, Co., Chapter 20, pp. 527-584 (1989) may be potentially used.

[0160] In addition to pressure-sensitive adhesives and tapes, this composition can also be used to form foam articles, such as foam carriers and tapes, as well as foam adhesives. In one aspect, the foam article is formed from a blend comprising (a) a precursor, (b) a liquid oligomer, and (c) expandable microspheres or a blowing agent. The microspheres can be expandable microspheres, for example, those available from Expansionl, Inc. Expandable microspheres. These microspheres are small, spherical rubber particles. Each microsphere comprises a polymer shell encapsulating blowing agent crystals. When the particles are heated, the blowing agent inside decomposes, releasing gas, which continues to cause the microspheres to expand like balloons. Expandable spheres within adhesive products create a foam structure.

[0161] Foaming agents can also be used in the manufacture of foamed products. Foaming agents can be selected from a wide range of materials, including physical and chemical foaming agents. Physical foaming agents, such as hydrocarbons, ethers, esters, etc., can include, for example, volatile liquids or compressed gases dissolved in polymers and whose state changes during processing. When physical foaming agents are included in adhesives, the change of state can create pores. Chemical foaming agents function by thermally decomposing during processing to release gases that form foam. Chemical foaming agents can be hydrazine derivatives that produce nitrogen in exothermic reactions. These chemical foaming agents include, but are not limited to, azodicarbonamide, sulfonyl hydrazine, p-tolueneaminourea, tetrazolium, substituted azonitrile compounds, and benzoxazine.

[0162] Will contain precursors and foaming agents / The pressure-sensitive adhesive composition is thoroughly mixed and then applied to a substrate at the desired coating weight. Depending on the viscosity of the blend, it can be applied at a temperature range of about 20°C to about 50°C or an elevated temperature range of about 51°C to about 170°C, or by applying a solution of the blend in a suitable solvent. The coating is then heat-treated in an oven to activate the foaming agent and initiate the condensation reaction. The residence time in the oven is adjusted as needed to allow the condensation reaction to continue until the desired cohesive strength is achieved. In many respects, the pressure-sensitive adhesive thus obtained exhibits high cohesive strength at room temperature and in an elevated temperature range of about 80°C to about 200°C.

[0163] The pressure-sensitive adhesives of this subject may further include additives such as pigments, fillers, plasticizers, diluents, antioxidants, etc. If desired, pigments are provided in an amount sufficient to impart the desired color to the adhesive. Examples of pigments include, but are not limited to, solid inorganic fillers such as carbon black, titanium dioxide, etc., as well as organic dyes. Other inorganic fillers such as aluminum trihydrate, cristobalite, glass fiber, kaolin, precipitated or calcined silica, copper, quartz, wollastonite, mica, magnesium hydroxide, silicates (e.g., feldspar), talc, nickel, and calcium carbonate are also useful. Metal oxides such as aluminum trihydrate and magnesium hydroxide are particularly useful as flame retardants and, unexpectedly, as agents for improving cohesive strength, especially at elevated temperatures (from about 80°C to about 200°C). These metal oxides may also potentially react with silane nuclei. Silanes are expected to condense and grow around the surface of the metal oxide particles, resulting in complete encapsulation.

[0164] Condensation catalysts can be used to accelerate the reaction, thereby forming a nucleus. Condensation catalysts are not particularly limited, but particularly include organotin compounds and their carboxylic acid metal salts, such as dibutyltin dilaurate, dibutyltin diacetylacetonate, dibutyltin dimaleate, dibutyltin diacetate, and dimethoxydibutyltin; organoaluminum compounds, such as aluminum triacetylacetonate, aluminum triacetoacetate, and aluminum diisopropoxyacetoacetate; organozirconium compounds, such as zirconium tetraacetylacetonate, zirconium tetraisopropoxide, and zirconium tetrabutoxide; titanates, such as tetrabutyl titanate and tetraisopropyl titanate; and amine compounds, such as butylamine, octylamine, dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, guanidine, diphenylguanidine, N-methylmorpholine, and 1,3-diazabicyclo[5.4.6]-undecene-7. The amount of the condensation catalyst added is optional, but can be up to 10% by weight of the preceding weight.

[0165] In this subject matter, the introduction of stabilizers is optional. Stabilizers can improve the can stability of the precursor and prevent premature condensation during storage, handling, and dispensing steps. These stabilizers include, but are not limited to, alcohols such as methanol, ethanol, isopropanol, and butanol; orthoesters such as trimethyl orthoacetate, triethyl orthoformate, and methyl orthoformate; oxazolidinyl compounds such as 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidinyl; vinyltrimethoxysilane; and carboxylic acids such as 2-ethylhexanoic acid. Stabilizers may be added to the precursor in amounts from about 0.01% by weight to about 15% by weight, or from 0.1% by weight to about 5% by weight, or from about 0.5% by weight to about 3% by weight.

[0166] In many respects, this subject matter provides a method for forming pressure-sensitive adhesives with hyperbranched silsesquioxane topologies using a thermal process. This method typically comprises a two-step process. The first step involves forming a precursor by providing a composition comprising at least one monomer having one or more olefinically unsaturated bonds, a thermal initiator, and a chain transfer agent, subjecting the composition to the activation temperature of the initiator until polymerization is substantially complete. The first step can be carried out in a solvent- or solvent-free environment. The second step comprises mixing the precursor obtained at least in the first step with a hydrolysis / condensation catalyst; casting the mixture onto a support mesh, and subsequently subjecting the composition to an elevated temperature range from about 51°C to about 200°C, thereby forming the adhesive of this subject matter.

[0167] In many respects, this subject matter provides a method for forming pressure-sensitive adhesives with hyperbranched silsesquioxane topologies using photochemical radiation. The method comprises a two-step process. The first step involves forming a precursor by providing a composition comprising at least one monomer having one or more olefinically unsaturated bonds, a photochemical radiation initiator, and a chain transfer agent, and exposing the composition to photochemical radiation at the activation wavelength of the initiator until polymerization is substantially complete. The first step can be carried out in a solvent- or solvent-free environment. The second step comprises mixing the precursor obtained at least in the first step with a hydrolysis / condensation catalyst; casting the mixture onto a support mesh; and subsequently subjecting the composition to an elevated temperature range from about 51°C to about 200°C, thereby forming the adhesive of this subject matter.

[0168] This subject matter also provides a method for forming a melt-processable composition that produces a pressure-sensitive adhesive having a hyperbranched silsesquioxane topology. In many respects, the method utilizes a solvent-free precursor that primarily comprises a silyl group located at one end of the precursor. The method further includes mixing the precursor with a hydrolysis / condensation catalyst to form the melt-processable composition. The method also includes casting the composition onto a carrier mesh and subsequently subjecting the composition to an elevated temperature range of about 51°C to about 200°C to form the adhesive of this subject matter.

[0169] The method also includes blending one or more fundamentally different precursors to form a pre-binder composition. The different precursors contain a silane group at one end of the precursor. The method further includes blending the precursor blend with a hydrolysis / condensation catalyst. The method also includes casting the composition onto a carrier mesh and subsequently subjecting the composition to an elevated temperature range of about 51°C to about 200°C to form the binder of this subject matter.

[0170] The method also includes blending a precursor or precursor mixture with a core modifier to form a pre-binder composition. The method further includes blending a precursor-core modifier mixture with a hydrolysis / condensation catalyst to form a pressure-sensitive adhesive composition. The method also includes casting the composition onto a carrier mesh and subsequently subjecting the composition to elevated temperatures (from about 51°C to about 200°C) to form the adhesive of this subject matter.

[0171] Pressure-sensitive adhesives can be used in adhesive articles such as labels, tapes, sheets, decorative decals, etc. In many respects, the article comprises a substrate having at least one side and a pressure-sensitive adhesive disposed in layers on at least a portion of the surface of the substrate. Suitable substrates used as a web carrier or adhesive carrier or face material for applying the adhesive include nonwoven materials such as paper, plastics, metals, or foams; and woven materials such as woven cotton or woven synthetic polymers, natural textiles, and synthetic textiles. Non-limiting examples of synthetic polymers include polyethylene, polypropylene, polyvinyl chloride, polyester, and polyamide. The adhesive can be applied to the substrate by any conventional method, including extrusion, spraying, roller coating, curtain coating, etc.

[0172] This subject matter provides various articles comprising the aforementioned compositions, precursors, and / or adhesives. Examples of such articles include adhesive sheets, foils, films, and tapes, including double-sided tapes, single-sided tapes, and transfer tapes; label preparation; label construction; automotive component bonding; wire harness tapes; permanent fastening adhesives; optically clear adhesives; electronic applications; medical applications; packaging products and components, including food packaging, packaging for household and industrial articles; and other articles.

[0173] Figure 16 and Figure 17 These are schematic cross-sectional views of articles 10 and 60, representing aspects of this subject matter. Article 10 includes a substrate or material 20 defining surfaces 22 and 24. A layer or region of pressure-sensitive adhesive 30 is disposed on at least one surface, such as surface 24. As described herein, the pressure-sensitive adhesive typically comprises a hyperbranched polymer containing a silsesquioxane core and / or a metal-silsesquioxane core. The PSA layer 30 typically defines an exposed surface 34 for bonding. Figure 17 The article 60 shown may include Figure 16 The article 10 comprises an article of material 10 and one or more protective release pads 50, which at least partially cover the exposed surface 34 of the PSA. Release pads are well known in the art and therefore will not be described herein.

[0174] Undoubtedly, many other benefits will become apparent from future applications and developments in this subject. The discovery of the unique properties of hyperbranched polymers has led to rapid advancements in this field over the past decade, but they have not been active in pressure-sensitive adhesives. The topological details that enable the most important special properties of hyperbranched polymers have been investigated. These include high levels of solubility and thermodynamic compatibility, low viscosity of solutions, anti-aggregation in solutions (including concentrated solutions), and function as nanocapsules for substances adsorbed within macromolecules. A key topological feature of hyperbranched polymers is the high volume concentration of chain units within the macromolecules due to branching without crosslinking. Furthermore, this volume concentration increases with increasing degree of branching. Thus, hyperbranched polymers are characterized by a weak dependence of the hydrodynamic volume of the macromolecules on molecular weight (compared to linear polymers), as higher molecular weights result in more compact molecular packing. This close packing of hyperbranched polymers, along with the numerous free ends of chains with functional groups on their periphery, represents the main structural and physical reason for their unique properties. Benefits associated with adhesives in this subject include the ability to process without the use of solvents, and the ability to achieve high peel, shear, and heat resistance. For example, a drawback of many conventional linear polymer-based PSAs, branched-linear PSAs, and randomly crosslinked adhesive networks is that peel strength and shear strength cannot be increased simultaneously. One comes at the expense of the other, thus limiting the adhesive and / or its properties. This topic provides methods to overcome these limitations of conventional PSAs.

[0175] Example

[0176] The adhesive properties of the various compositions described below are evaluated using the test methods listed in Table 1.

[0177] Table 1 - Test methods for tape performance

[0178] Test conditions

[0179] 180° Peeling a. Peeling: Apply the sample to a stainless steel plate using a 5-pound roller, once in each direction. The sample is conditioned and tested at 23°C.

[0180] Shear strength a. Room temperature shear: 1 kg weight, 0.5 inch × 0.5 inch overlap. Apply the sample to a stainless steel plate using a 5 lb roller, once in each direction. The sample is conditioned and tested at 23°C.

[0181] To further illustrate various aspects of this subject matter, the following embodiments are provided. These embodiments are intended only to illustrate methods and aspects of this subject matter and should not be construed as limiting the scope of the claims.

[0182] Precursor Synthesis

[0183] Example 1

[0184] In a glass reactor, 10 g of n-butyl acrylate, 0.001 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.012 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to UV radiation at 365 nm for 4 hours to obtain the precursor in high yield.

[0185] Example 2

[0186] In a glass reactor, 10 g of n-butyl acrylate, 0.005 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.012 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to UV radiation at 365 nm for 4 hours to obtain the precursor in high yield.

[0187] Example 3

[0188] In a glass reactor, 10 g of n-butyl acrylate, 0.0028 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.04 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to 365 nm UV radiation for 4 hours to obtain the precursor in high yield.

[0189] Example 4

[0190] In a glass reactor, 7.5 g of n-butyl acrylate, 2.5 g of isobornyl acrylate, 0.002 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.03 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to 365 nm UV radiation for 4 hours to obtain the precursor in high yield.

[0191] Example 5

[0192] In a glass reactor, 5.8 g of n-butyl acrylate, 4.2 g of tert-butyl acrylate, 0.002 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.03 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to 365 nm UV radiation for 4 hours to obtain the precursor in high yield.

[0193] Example 6

[0194] In a glass reactor, 4.9 g of n-butyl acrylate, 2.1 g of tert-butyl acrylate, 0.0014 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 0.035 g of 3-mercaptopropyltrimethoxysilane were added. The reactor contents were inertized with nitrogen for 5 minutes. The contents were then exposed to 365 nm UV radiation for 4 hours to obtain the precursor in high yield.

[0195] Example 7

[0196] In a glass reactor, 3.66 g of methyl methacrylate, 4.53 g of n-butyl acrylate, 1.0 g of 2-hydroxyethyl methacrylate, 1.2 g of 3-mercaptopropyltrimethoxysilane, 0.15 g of azobisisobutyronitrile, and 45 ml of tetrahydrofuran were added. The reactor contents were inertized with nitrogen for 5 minutes. The mixture was heated at 60 °C for 6 hours. The solvent was removed in a rotary evaporator to obtain the precursor in high yield.

[0197] In Table 2, conversion rates were determined by gas chromatography, and molecular weights were determined by gel permeation chromatography. The sample was dissolved in tetrahydrofuran (THF) at approximately 0.2% by weight. The sample was then injected into a GPC instrument using THF as the mobile phase. The column was calibrated using polystyrene standards. Toluene was used as an internal standard.

[0198] Table 2 - Conversion rates, molecular weights, and polydispersity (PDI) of Examples 1-7

[0199]

[0200] Synthesis of hyperbranched silsesquioxane pressure-sensitive adhesives

[0201] Example 8

[0202] 10g of precursor 7 was dissolved in 2g of ethyl acetate. Then, 0.015g of Tyzor AA 105 was added to the precursor solution. The solution was cast onto a silicone release liner and then dried in a convection oven at 150°C for 5 minutes. After drying, the resulting material was a non-stick coating with a Tg of 12.5°C as determined by DSC and a shear modulus of 1×10⁻⁶ as determined by DMA. 8 dynes / cm 2 Both of these values ​​are outside the PSA range.

[0203] Example 9

[0204] Dissolve 10g of precursor 4 in 5g of ethyl acetate. Then add 0.015g of Tyzor AA 105 to the precursor solution. Cast the solution onto a silicone release liner and then dry it in a convection oven at 150°C for 5 minutes to obtain a pressure-sensitive adhesive in the form of a transfer tape.

[0205] Example 10

[0206] Dissolve 10g of precursor 5 in 5g of ethyl acetate. Then add 0.015g of Tyzor AA 105 to the precursor solution. Cast the solution onto a silicone release liner and then dry it in a convection oven at 150°C for 5 minutes to obtain a pressure-sensitive adhesive in the form of a transfer tape.

[0207] Further testing showed that the shear modulus and glass transition temperature of the material in Example 8 were outside the PSA range.

[0208] Table 3 - Peel and Shear Properties of Hyperbranched Silsesquioxane Pressure-Sensitive Adhesives

[0209]

[0210] Synthesis of Hybrid Hyperbranched Metal-Silsesquioxane Pressure-Sensitive Adhesives

[0211] Example 11

[0212] 10g of precursor 6 was dissolved in 3.5g of ethyl acetate and 1.5g of isopropanol. Then 0.55g of Tyzor AA 105 was added to the precursor solution. The solution was cast onto a silicone release liner and then dried in a convection oven at 150°C for 5 minutes to obtain a pressure-sensitive adhesive in the form of a transfer tape.

[0213] Table 4 - Peel and Shear Properties of Hyperbranched Metal-Silsesquioxane Pressure-Sensitive Adhesives Example Peel (180° on stainless steel) lb / in Shear (0.5” × 0.5”, 1kg) min 11 3.7 >30,000

[0214] GPC analysis is a good technique for estimating the number of silicon atoms in the core of a silsesquioxane. The condensate is dissolved in a GPC solvent, and the molecular weight of the sol portion is then determined. By comparing the molecular weight of the precursor with that of the condensate, the number of silicon atoms in the core is directly indicated. In the examples described above, this value is typically between 6 and 8. However, it should be understood that the subject matter is by no means limited to this range.

[0215] Undoubtedly, many other benefits will become apparent from the future application and development of this technology.

[0216] Other embodiments consistent with this teaching are listed in the following numbered clauses.

[0217] Clause 1. A polymer comprising a hyperbranched polymer, said hyperbranched polymer comprising at least one silsesquioxane core and at least two polymer chains chemically bonded to each of said silsesquioxane cores.

[0218] Clause 2. The polymer according to Clause 1, wherein the silsesquioxane core is selected from the group consisting of: pure silsesquioxane cores, hybrid silsesquioxane cores, and combinations thereof.

[0219] Clause 3. The polymer according to any one of Clauses 1-2, wherein the silsesquioxane core is selected from the group consisting of: fully condensed cores, partially condensed cores, and combinations thereof.

[0220] Clause 4. The polymer according to any one of Clauses 1-3, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by atoms M of a core modifier having the formula selected from the group consisting of: MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, wherein R is selected from the group consisting of: alkyl, alkenyl, aryl, H, and combinations thereof, M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, and X is selected from the group consisting of: organic monodentate ligands, organic bidentate ligands, organic tridentate ligands, organic amphipathic ligands, halogens, alkoxides, and combinations thereof.

[0221] Clause 5. The polymer according to any one of Clauses 1-4, wherein the silsesquioxane core comprises a hybrid core, wherein one or more Si atoms in the hybrid core are replaced by atoms M of a core modifier having the formula selected from the group consisting of: M(X)4 and M(X). a (Z) b M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, a is 2, b is 2, X is a hydrolyzable group, and Z is a compound of formula AC(O)-(R'). n -C(O)-B organic ligands, where R' is an organic group, n is an integer from 0 to 10, A is an organic group, and B is an organic group.

[0222] Clause 6. The polymer according to any one of Clauses 1-5, wherein the silsesquioxane core comprises a hybrid core, wherein one or more Si atoms in the hybrid core are replaced by another Si atom of a core modifier having the formula R". 4-q Si(OR#) q , where R” is a functional or nonfunctional hydrocarbon group, R# is selected from the group consisting of: methyl, ethyl and isopropyl, and q is 2 or 3.

[0223] Clause 7. The polymer according to any one of Clauses 1-6, wherein the silsesquioxane core comprises a hybrid core, wherein one or more Si atoms in the hybrid core are replaced by another Si atom of a core modifier having the formula Si(OR#)4, wherein R# is selected from the group consisting of methyl, ethyl and isopropyl.

[0224] Clause 8. The polymer according to any one of Clauses 1-7, wherein each of the polymer chains comprises polymers selected from the group consisting of: different polymer chains, identical polymer chains, and combinations thereof.

[0225] Clause 9. The polymer according to any one of Clauses 1-8, wherein the polymer chain along the main chain of the polymer chain is free of any olefinic unsaturation or acrylate unsaturation.

[0226] Clause 10. The polymer according to any one of Clauses 1-9, wherein the polymer chain comprises (meth)acrylate monomers linked to form a polymer selected from the group consisting of: linear homopolymers, branched homopolymers, linear copolymers, branched copolymers, and combinations thereof.

[0227] Clause 11. The polymer according to any one of Clauses 1-10, wherein the hyperbranched polymer and at least one of the polymers comprises at least about 50% by weight of (meth)acrylate monomer.

[0228] Clause 12. The polymer according to any one of Clauses 1-11, further comprising an oligomer having at least one crosslinkable functional group.

[0229] Clause 13. The polymer according to Clause 12, wherein the oligomer is a liquid at room temperature.

[0230] Clause 14. The polymer according to any one of Clauses 12-13, wherein the oligomer has a backbone selected from the group consisting of: polyethers, polyisobutylene, amorphous polyalphaolefins, polybutadiene, polyisoprene, polydimethylsiloxane, polyalkyloxazoline, polyesters, poly(meth)acrylates, polyurethanes, and combinations thereof.

[0231] Clause 15. The polymer according to any one of Clauses 1-14, further comprising a tackifier.

[0232] Clause 16. The polymer according to any one of Clauses 1-15, wherein the silsesquioxane core is a pure silsesquioxane core.

[0233] Clause 17. The polymer according to any one of Clauses 1-16, wherein the pure silsesquioxane core comprises only a fully condensed core.

[0234] Clause 18. The polymer according to any one of Clauses 1-16, wherein the pure silsesquioxane core comprises only a partially condensed core.

[0235] Clause 19. The polymer according to any one of Clauses 1-16, wherein the pure silsesquioxane core comprises a combination of a fully condensed core and a partially condensed core.

[0236] Clause 20. The polymer according to any one of Clauses 1-15, wherein the silsesquioxane core is a hybrid silsesquioxane core.

[0237] Clause 21. The polymer according to any one of Clauses 1-15 and 20, wherein the hybrid silsesquioxane core comprises only a fully condensed core.

[0238] Clause 22. The polymer according to any one of Clauses 1-15 and 20, wherein the hybrid silsesquioxane core comprises only a partially condensed core.

[0239] Clause 23. The polymer according to any one of Clauses 1-15 and 20, wherein the hybrid silsesquioxane core comprises a combination of a fully condensed core and a partially condensed core.

[0240] Clause 24. The polymer according to any one of Clauses 1-15, wherein the silsesquioxane core comprises a combination of a pure silsesquioxane core and a hybrid silsesquioxane core.

[0241] Clause 25. The polymer according to any one of Clauses 1-15 and 24, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises only fully condensed cores.

[0242] Clause 26. The polymer according to any one of Clauses 1-15 and 24, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises only partially condensed cores.

[0243] Clause 27. The polymer according to any one of Clauses 1-15 and 24, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises a combination of fully condensed cores and partially condensed cores.

[0244] Clause 28. The polymer according to any one of Clauses 1-27, wherein the silsesquioxane core comprises a Si atom attached to at least one of three oxo groups and two oxo groups.

[0245] Clause 29. The polymer according to any one of Clauses 1-28, wherein the silsesquioxane core has the general formula [RSiO 3 / 2 ] n , where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0246] Clause 30. The polymer according to any one of Clauses 1-29, wherein most of the silsesquioxane cores have the general formula [RSiO 3 / 2 ] n , where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0247] Clause 31. The polymer according to any one of Clauses 1-28, wherein the silsesquioxane core has the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where “n” is a positive integer, “x” is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0248] Clause 32. The polymer according to any one of Clauses 1-28 and 30, wherein most of the silsesquioxane cores have the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where “n” is a positive integer, “x” is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0249] Clause 33. The polymer according to any one of Clauses 2-15 and 20-30, wherein the hybrid silsesquioxane core is a metal-silsesquioxane core.

[0250] Clause 34. The polymer according to any one of Clauses 1-33, wherein the silsesquioxane core is at least one of a cage-like, polymeric form, or combination thereof.

[0251] Clause 35. The polymer according to any one of Clauses 1-34, wherein each of the silsesquioxane cores of a portion of the hyperbranched polymer is connected in series with and covalently linked to another silsesquioxane core to form a beaded structure.

[0252] Clause 36. The polymer according to Clause 35, wherein the link comprises a polyol having the following structure:

[0253]

[0254] Where R is a spacer group located between OH groups, and n is selected from the following groups: 2, 3, 4 and their combinations.

[0255] Clause 37. The polymer according to any one of Clauses 1-34, wherein each of the silsesquioxane cores of a portion of the hyperbranched polymer is covalently linked to one or more other silsesquioxane cores to form a multidimensional network structure.

[0256] Clause 38. The polymer according to Clause 37, wherein the link comprises a hydrolyzable disilane having the following structure:

[0257]

[0258] Where R is an organic group located between two hydrolyzable silane moieties, X is a hydrolyzable group, Y is an organic functional group, and each "a" is independently selected from 0, 1, and 2.

[0259] Clause 39. The polymer according to any one of Clauses 37-38, wherein the multidimensional network is a two-dimensional structure.

[0260] Clause 40. The polymer according to any one of Clauses 1-39, wherein the number-average molecular weight (Mn) of said polymer is in the range of about 20,000 to about 1,000,000 g / mol.

[0261] Clause 41. The polymer according to any one of Clauses 1-40, wherein the polymer is not crosslinked.

[0262] Clause 42. The polymer according to any one of Clauses 1-41, wherein the polymer exhibits a glass transition temperature (Tg) of about 10°C to about -60°C as determined by differential scanning calorimetry (DSC).

[0263] Clause 43. The polymer according to any one of Clauses 1-42, wherein the polymer exhibits a strength of 5 × 10⁻⁶ as determined by dynamic mechanical analysis (DMA) at 25°C and 1 radians / second. 4 -6×10 6 dynes / cm 2 The platform shear modulus.

[0264] Clause 44. A pressure-sensitive adhesive comprising a polymer according to any one of Clauses 1-43.

[0265] Clause 45. An article comprising the pressure-sensitive adhesive as described in Clause 44.

[0266] Clause 46. The article of manufacture described in Clause 45 further comprises:

[0267] Substrate with defined surfaces;

[0268] The pressure-sensitive adhesive is disposed on at least a portion of the surface of the substrate.

[0269] Clause 47. A method of forming a polymer, comprising the following steps:

[0270] Provide a precursor with the following formula:

[0271] R-Si(X) 3-a (Y) a

[0272] Where R is one of the following: non-hydrolyzable organic groups, non-hydrolyzable oligomer chains, and non-hydrolyzable polymer chains; X is a hydrolyzable group; Y is an organic functional group; and the value of "a" is selected from the group consisting of 0, 1, 2, and their combinations.

[0273] The precursor is subjected to hydrolysis and condensation reactions, or condensation reactions only, to form a hyperbranched polymer containing a silsesquioxane core.

[0274] Clause 48. The method according to Clause 47, wherein the step of providing the precursor comprises polymerizing (meth)acrylate monomers in the presence of a free radical initiator and a silane-containing chain transfer agent (CTA).

[0275] Clause 49. The method according to Clause 48, wherein the molar ratio of CTA to initiator is about 200:1 to about 1:2.

[0276] Clause 50. The method according to any one of Clauses 48-49, wherein the chain transfer agent (CTA) has the following structure:

[0277] Where R is the organic linking group located between the thiol and the hydrolyzable silane moiety, X is the hydrolyzable group, Y is the organic functional group, and the value of "a" is selected from the group consisting of 0, 1, 2 and their combinations.

[0278] Clause 51. The method according to any one of Clauses 48-50, wherein the initiator is activated upon exposure to at least one of heat, photochemical radiation, and electron beam radiation.

[0279] Clause 52. The method according to any one of Clauses 48-51, wherein the initiator is activated upon exposure to UV radiation.

[0280] Clause 53. The method according to any one of Clauses 47-52, wherein the hydrolysis and the condensation reaction, or only the condensation reaction, occur at a temperature range of about 20°C to about 50°C and about 51°C to about 170°C.

[0281] Clause 54. The method according to any one of Clauses 47-53, wherein the hydrolysis and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst.

[0282] Clause 55. The method according to Clause 54, wherein the amount of said catalyst is from about 0.5% by weight to about 5% by weight of said precursor.

[0283] Clause 56. The method according to any one of Clauses 47-55, wherein the precursor comprises a macromolecular monomer having the following general formula:

[0284] X"-(Y") n -Z

[0285] Where X" is a vinyl group that can copolymerize with other monomers present in the precursor composition; Y" is a divalent linker group, where n is 0 or 1; Z is a monovalent polymer moiety, whose T g Above 20°C and with a weight-average molecular weight in the range of about 2,000 to about 30,000 g / mol.

[0286] Clause 57. The method according to any one of Clauses 47-56, wherein the silsesquioxane core is selected from the group consisting of: pure silsesquioxane cores, hybrid silsesquioxane cores, and combinations thereof.

[0287] Clause 58. The method according to any one of Clauses 47-57, wherein the silsesquioxane core is selected from the group consisting of: fully condensed cores, partially condensed cores, and combinations thereof.

[0288] Clause 59. The method according to any one of Clauses 47-58 further comprises:

[0289] A core modifier is provided before and / or during the hydrolysis and condensation reaction of the precursor, or only the condensation reaction.

[0290] Clause 60. The method according to Clause 59, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by atoms M of the core modifier, the core modifier having a formula selected from the group consisting of: MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, wherein R is selected from the group consisting of: alkyl, alkenyl, aryl, H, and combinations thereof, M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, and X is selected from the group consisting of: organic monodentate ligands, organic bidentate ligands, organic tridentate ligands, organic amphipathic ligands, halogens, alkoxides, and combinations thereof.

[0291] Clause 61. The method according to any one of Clauses 59-60, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by atoms M of the core modifier, the core modifier having the formula selected from the group consisting of: M(X)4 and M(X). a (Z) b M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, a is 2, b is 2, X is a hydrolyzable group, and Z is a compound of formula AC(O)-(R'). n -C(O)-B organic ligands, where R' is an organic group, n is an integer from 0 to 10, A is an organic group, and B is an organic group.

[0292] Clause 62. The method according to any one of Clauses 59-61, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by another Si atom of the core modifier having the formula R". 4-q Si(OR#) q , where R" is a functional or nonfunctional hydrocarbon group, R# is selected from the group consisting of: methyl, ethyl and isopropyl, and q is 2 or 3.

[0293] Clause 63. The method according to any one of Clauses 59-62, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by another Si atom of the core modifier having the formula Si(OR#)4, wherein R# is selected from the group consisting of methyl, ethyl and isopropyl.

[0294] Clause 64. The method according to any one of Clauses 47-63, wherein the polymer chain comprises polymers selected from the group consisting of: different polymer chains, the same polymer chains, and combinations thereof.

[0295] Clause 65. The method according to any one of Clauses 47-64, wherein the polymer chain contains no olefinic unsaturation or acrylate unsaturation along the main chain of the polymer chain.

[0296] Clause 66. The method according to any one of Clauses 47-65, wherein the polymer chain comprises (meth)acrylate monomers linked to form a polymer selected from the group consisting of: linear homopolymers, branched homopolymers, linear copolymers, branched copolymers, and combinations thereof.

[0297] Clause 67. The method according to any one of Clauses 47-66, wherein the hyperbranched polymer and at least one of the polymers comprises at least about 50% by weight of (meth)acrylate monomer.

[0298] Clause 68. The method according to any one of Clauses 47-67, further comprising the step of adding an oligomer having at least one crosslinkable functional group in addition to the precursor.

[0299] Clause 69. The method according to Clause 68, wherein the oligomer is a liquid at room temperature.

[0300] Clause 70. The method according to any one of Clauses 47-69, wherein the oligomer has a main chain selected from the group consisting of: polyethers, polyisobutylene, amorphous polyalphaolefins, polybutadiene, polyisoprene, polydimethylsiloxane, polyalkyloxazoline, polyesters, poly(meth)acrylates, polyurethanes, and combinations thereof.

[0301] Clause 71. The method according to any one of Clauses 47-70 further includes the step of adding a tackifier.

[0302] Clause 72. The method according to Clause 71, wherein the tackifier is substantially compatible with the precursor.

[0303] Clause 73. The method according to any one of Clauses 47-72, wherein the silsesquioxane core is a pure silsesquioxane core.

[0304] Clause 74. The method according to any one of Clauses 47-73, wherein the pure silsesquioxane core comprises only a fully condensed core.

[0305] Clause 75. The method according to any one of Clauses 47-73, wherein the pure silsesquioxane core comprises only a partially condensed core.

[0306] Clause 76. The method according to any one of Clauses 47-75, wherein the pure silsesquioxane core comprises a combination of a fully condensed core and a partially condensed core.

[0307] Clause 77. The method according to any one of Clauses 47-72, wherein the silsesquioxane core is a hybrid silsesquioxane core.

[0308] Clause 78. The method according to any one of Clauses 47-72 and 77, wherein the hybrid silsesquioxane core comprises only a fully condensed core.

[0309] Clause 79. The method according to any one of Clauses 47-72 and 77, wherein the hybrid silsesquioxane core comprises only a partially condensed core.

[0310] Clause 80. The method according to any one of Clauses 47-72 and 77, wherein the hybrid silsesquioxane core comprises a combination of a fully condensed core and a partially condensed core.

[0311] Clause 81. The method according to any one of Clauses 47-72, wherein the silsesquioxane core comprises a combination of a pure silsesquioxane core and a hybrid silsesquioxane core.

[0312] Clause 82. The method according to any one of Clauses 47-72 and 81, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises only fully condensed cores.

[0313] Clause 83. The method according to any one of Clauses 47-72 and 81, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises only partially condensed cores.

[0314] Clause 84. The method according to any one of Clauses 47-72 and 81, wherein the combination of the pure silsesquioxane core and the hybrid silsesquioxane core comprises a combination of fully condensed cores and partially condensed cores.

[0315] Clause 85. The method according to any one of Clauses 47-84, wherein the silsesquioxane core comprises a Si atom attached to at least one of three oxo groups and two oxo groups.

[0316] Clause 86. The method according to any one of Clauses 47-85, wherein the silsesquioxane core has the general formula [RSiO 3 / 2 ] n , where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0317] Clause 87. The method according to any one of Clauses 47-86, wherein most of the silsesquioxane cores have the general formula [RSiO3 / 2 ] n , where n is an even number, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0318] Clause 88. The method according to any one of Clauses 47-85, wherein the silsesquioxane core has the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where “n” is a positive integer, “x” is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0319] Clause 89. The method according to any one of Clauses 47-85 and 88, wherein most of the silsesquioxane cores have the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where “n” is a positive integer, “x” is a positive integer value less than or equal to 3n / 2, and R is selected from the group consisting of: alkyl, aryl, heterohydrocarbon, polymer, oligomer, (meth)acrylate polymer, (meth)acrylate oligomer and combination thereof.

[0320] Clause 90. The method according to any one of Clauses 57-72 and 77-89, wherein the hybrid silsesquioxane core is a metal-silsesquioxane core.

[0321] Clause 91. The method according to any one of Clauses 47-90, wherein the silsesquioxane core is at least one of a cage-like, polymeric, or combination thereof.

[0322] Clause 92. The method according to any one of Clauses 47-91, further comprising the step of: adding a certain amount of polyol during the condensation reaction to tandem and covalently link each of the silsesquioxane cores of a portion of the hyperbranched polymer with another silsesquioxane core to form a beaded structure, the polyol having the following structure:

[0323]

[0324] Where R is a spacer group located between OH groups, and n is selected from the following groups: 2, 3, 4 and their combinations.

[0325] Clause 93. The method according to Clause 92, wherein the amount of said polyol is from about 0% by weight to about 30% by weight of the hyperbranched polymer and at least one of said polymers.

[0326] Clause 94. The method according to any one of Clauses 47-91, further comprising the step of: adding a certain amount of hydrolyzable disilane during the condensation reaction to connect each of the silsesquioxane cores of a portion of the hyperbranched polymer to one or more other silsesquioxane cores to form a multidimensional network structure, the hydrolyzable disilane having the following structure:

[0327]

[0328] Where R is an organic group located between two hydrolyzable silane moieties, X is a hydrolyzable group, Y is an organic functional group, and each "a" is independently selected from 0, 1, and 2.

[0329] Clause 95. The method described in Clause 94, wherein the multidimensional network is a two-dimensional structure.

[0330] Clause 96. The method according to any one of Clauses 94-95, wherein the amount of the hydrolyzable disilane is from about 0% by weight to about 30% by weight of the hyperbranched polymer and at least one of the polymers.

[0331] Clause 97. The method according to any one of Clauses 47-96, wherein X is selected from the group consisting of: halogens, acyloxy groups, ketooxime ester groups, alkoxy groups, and combinations thereof.

[0332] Clause 98. The method according to any one of Clauses 47-97, wherein X is an alkoxy group.

[0333] Clause 99. The method according to any one of Clauses 47-98, wherein the value of “a” is 0.

[0334] Clause 100. The method according to any one of Clauses 47-99, wherein the number-average molecular weight (Mn) of said precursor is in the range of about 2,000 to about 300,000 g / mol.

[0335] Clause 101. The method according to any one of Clauses 47-100, wherein the number-average molecular weight (Mn) of said polymer is in the range of about 20,000 to about 1,000,000 g / mol.

[0336] Clause 102. The method according to any one of Clauses 47-101, wherein the precursor is synthesized in one of a solvent medium and a solvent-free medium.

[0337] Clause 103. The method according to any one of Clauses 47-102, wherein the polymer is not crosslinked.

[0338] Clause 104. The method according to any one of Clauses 47-103, wherein the polymer exhibits a glass transition temperature (Tg) of about 10°C to about -60°C as determined by differential scanning calorimetry (DSC).

[0339] Clause 105. The method according to any one of Clauses 47-104, wherein said polymer exhibits a strength of 5 × 10⁻⁶ as determined by dynamic mechanical analysis (DMA) at 25°C and 1 radians / second. 4 -6×10 6 dynes / cm 2 The platform shear modulus.

[0340] Clause 106. A pressure-sensitive adhesive comprising a polymer formed by any one of Clauses 47-105.

[0341] Clause 107. A pressure-sensitive adhesive comprising a hyperbranched polymer, said hyperbranched polymer comprising at least one silsesquioxane core and at least two polymer chains chemically bonded to each of said silsesquioxane cores.

[0342] The hyperbranched polymer and the pressure-sensitive adhesive contain at least about 50% by weight of (meth)acrylate monomer.

[0343] Clause 108. The pressure-sensitive adhesive as described in Clause 107, wherein the polymer is not cross-linked.

[0344] Clause 109. A pressure-sensitive adhesive comprising a hyperbranched polymer having at least one silsesquioxane core and at least two polymer chains chemically bonded to each of the silsesquioxane cores.

[0345] The hyperbranched polymer and the pressure-sensitive adhesive contain at least about 50% by weight of (meth)acrylate monomer.

[0346] Clause 110. The pressure-sensitive adhesive as described in Clause 109, wherein the polymer is not cross-linked.

[0347] The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more aspects. For example, references to "certain aspects," "some aspects," or similar language throughout this specification mean that a particular feature, structure, or characteristic described in connection with that aspect is included in at least one aspect of the invention. Therefore, the phrases "in some aspects," "in some aspects," "in other aspects," or similar language appearing throughout this specification do not necessarily refer to the same set of aspects, and the described features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0348] As stated above, this subject matter addresses many problems associated with prior strategies, systems, and / or devices. However, it should be understood that various changes can be made by those skilled in the art to the details, materials, and arrangements of the components and / or operations described and illustrated herein to explain the nature of this subject matter, without departing from the principles and scope of the claimed subject matter as set forth in the appended claims.

Claims

1. A pressure-sensitive adhesive comprising one or more hyperbranched polymers exhibiting a core-shell structure comprising at least one silsesquioxane core and at least two polymer chains chemically bonded to each of the silsesquioxane cores, the shell comprising at least two polymer chains; At least two polymer chains emanate from the silsesquioxane core to form a hyperbranched polymer, such that one end of each polymer chain is chemically bonded to the silsesquioxane core while allowing the other end to dangle freely. The hyperbranched polymers mentioned above are discrete molecules. The polymer chain described herein contains no olefinic unsaturation along its main chain. The polymer chains thereon are not cross-linked. The hyperbranched polymer is formed from a hydrolyzable and condensable, or condensable-only, precursor having the following formula: R-Si(X) 3-a (AND) a Where R is a non-hydrolyzable polymer chain comprising a polymer formed by the linkage of (meth)acrylate monomers, X is a hydrolyzable group, Y is an organic functional group, and the value of "a" is 0. Where X is selected from the group consisting of the following: halogens, acyloxy groups, ketooxime ester groups, alkoxy groups, and combinations thereof. The precursor has a single terminal silane unit or group, and The number-average molecular weight Mn of the precursor is in the range of 2,000 to 300,000 g / mol.

2. The pressure-sensitive adhesive according to claim 1, wherein the precursor is a reaction product comprising a mixture of the following: (i) one or more (meth)acrylate monomers; (ii) Free radical initiators; and (iii) Silane-containing chain transfer agent CTA; The molar ratio of CTA to the free radical initiator is 200:1 to 1:

2. The structure of the CTA is as follows: Where R is the organic linking group located between the thiol and the hydrolyzable silane moiety, X is the hydrolyzable group, Y is the organic functional group, and the value of "a" is 0; Where X is selected from the group consisting of halogens, acyloxy groups, ketooxime ester groups, alkoxy groups, and combinations thereof, and The free radical initiator can be activated upon exposure to at least one of heat, photochemical radiation, and electron beam radiation.

3. The pressure-sensitive adhesive according to claim 2, wherein one or more of the following (A)-(F) are applicable: (A) The free radical initiator is an initiator that can be activated by photochemical radiation; (B) The free radical initiator is an initiator that can be thermally activated; (C) The mixture contains no solvent; (D) The mixture contains a solvent; (E) The mixture contains a solvent, and the solvent is an inert θ solvent; or (F) The precursor is prepared by a one-step reaction.

4. The pressure-sensitive adhesive according to claim 2, wherein one or more of the following (A)-(I) are applicable: (A) The precursor is hydrolyzable and condensable, or only condensable, at a temperature between 20°C and 50°C and between 51°C and 170°C. (B) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst and a core modifier; (C) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst and a core modifier, and the amount of the catalyst is 0.5% to 5% by weight of the precursor. (D) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst and a core modifier, and the core modifier has a molecular formula selected from the group consisting of: MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, wherein R is selected from the group consisting of alkyl, alkenyl, aryl, H, and combinations thereof, M is independently selected from Al, Ge, Sn, Ti, and Zr, and X is an alkoxide; (E) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst and a core modifier, wherein the core modifier is an alkoxy titanium having the formula Ti(OR')4, wherein R' is selected from the group consisting of ethyl, isopropyl, and butyl and combinations thereof; (F) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a solvent; (G) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a solvent, and the solvent is an inert θ solvent; or (H) The hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the absence of a solvent.

5. The pressure-sensitive adhesive according to claim 1, further comprising a tackifier.

6. The pressure-sensitive adhesive of claim 1, wherein each of the silsesquioxane cores of a portion of the hyperbranched polymer is connected in series with and covalently linked to another silsesquioxane core to form a beaded structure. Optionally, the link comprises a polyol having the following structure: Where R is a spacer group located between OH groups, and n is selected from the following groups: 2, 3, 4 and their combinations.

7. The pressure-sensitive adhesive of claim 1, wherein each of the silsesquioxane cores of a portion of the hyperbranched polymer is covalently linked to one or more other silsesquioxane cores to form a multidimensional network structure, optionally wherein one or both of the following (A)-(B) are applicable: (A) The connection comprises a hydrolyzable disilane having the following structure: Where R is an organic group located between two hydrolyzable silane moieties, X is a hydrolyzable group, Y is an organic functional group, and each "a" is independently selected from 0, 1, and 2; (B) The multidimensional network is a two-dimensional structure.

8. The pressure-sensitive adhesive according to claim 1, wherein any one of the following (A)-(Q) is applicable: (A) The silsesquioxane core is selected from the group consisting of: pure silsesquioxane cores, hybrid silsesquioxane cores and combinations thereof, and optionally the silsesquioxane core is selected from the group consisting of: fully condensed cores, partially condensed cores and combinations thereof. (B) The silsesquioxane core comprises a hybrid core in which one or more Si atoms are replaced by atoms M of a core modifier having a molecular formula selected from the group consisting of: MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, wherein R is selected from the group consisting of: alkyl, alkenyl, aryl, H, and combinations thereof, M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, and X is selected from the group consisting of: organic monodentate ligands, organic bidentate ligands, organic tridentate ligands, and combinations thereof; (C) The silsesquioxane core comprises a hybrid core in which one or more Si atoms are replaced by atoms M of a core modifier having a molecular formula selected from the group consisting of: M(X)4 and M(X). a (Z) b M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, a is 2, b is 2, X is a hydrolyzable group, and Z is a compound of formula AC(O)-(R'). n -C(O)-B organic ligands, where R' is an organic group, n is an integer from 0 to 10, A is an organic group, and B is an organic group; (D) The silsesquioxane core comprises a hybrid core, wherein one or more Si atoms in the hybrid core are replaced by another Si atom of a core modifier having the formula R". 4-q Si(OR#) q , where R" is a functional or nonfunctional hydrocarbon group, R# is selected from the group consisting of: methyl, ethyl and isopropyl, and q is 2 or 3; (E) The silsesquioxane core comprises a hybrid core in which one or more Si atoms are replaced by another Si atom of a core modifier having the formula Si(OR#)4, wherein R# is selected from the group consisting of methyl, ethyl and isopropyl. (F) The polymer chain comprises a polymer formed by linking (meth)acrylate monomers, the polymer being selected from the group consisting of: linear homopolymers, branched homopolymers, linear copolymers, branched copolymers, and combinations thereof; (G) The polymer chain is composed of (meth)acrylate polymer chains; (H) The pressure-sensitive adhesive contains at least 50% by weight of (meth)acrylate monomer; (I) The pressure-sensitive adhesive further comprises an oligomer having at least one crosslinkable functional group. Optionally, the oligomer is a liquid at room temperature, and Optionally, the oligomer has a backbone selected from the group consisting of: polyethers, amorphous polyalphaolefins, polybutadiene, polyisoprene, polydimethylsiloxane, polyalkyloxazoline, polyesters, poly(meth)acrylates, polyurethanes, and combinations thereof. (J) The fully condensed silsesquioxane core has the general formula [RSiO 3 / 2 ] n , where n is an even number and R is a polymer chain; (K) The partially condensed silsesquioxane core has the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where "n" is a positive integer, "x" is a positive integer value less than 3n / 2, and R is a polymer chain; (L) The silsesquioxane core is at least one of cage-like, polymeric, ladder-like, or combinations thereof; (M) The number-average molecular weight Mn of the precursor, as determined by gel permeation chromatography, is from 59,495 to 300,000 g / mol. (N) The number-average molecular weight Mn of the precursor was determined by gel permeation chromatography to be in the range of 30,078 to 88,024 g / mol; (O) The number-average molecular weight Mn of the pressure-sensitive adhesive is in the range of 20,000 to 1,000,000 g / mol, as determined by gel permeation chromatography. (P) The pressure-sensitive adhesive exhibits a glass transition temperature Tg of -60°C to 10°C, as determined by differential scanning calorimetry (DSC); or (Q) The pressure-sensitive adhesive exhibits a dynamic mechanical strength of 5 × 10⁻⁶ at 25°C and 1 radians / second, as determined by DMA. 4 -6×10 6 dynes / cm 2 The platform shear modulus.

9. The pressure-sensitive adhesive according to claim 8, wherein X in (B) is an organic amphipathic ligand.

10. The pressure-sensitive adhesive according to claim 8, wherein the organic monodentate ligand in (B) is a halogen.

11. The pressure-sensitive adhesive according to claim 8, wherein X in (B) is an alkoxide.

12. The pressure-sensitive adhesive according to claim 8, wherein the amorphous poly-α-olefin in (I) is polyisobutylene.

13. The pressure-sensitive adhesive according to claim 8, wherein R in (J) is a (meth)acrylate polymer chain.

14. The pressure-sensitive adhesive according to claim 8, wherein R in (K) is a (meth)acrylate polymer chain.

15. A method for forming a pressure-sensitive adhesive, comprising the following steps: Provide the precursor as defined in claim 1, The precursor is subjected to hydrolysis and condensation reactions or only condensation reactions to form a hyperbranched polymer containing a silsesquioxane core. The hyperbranched polymer exhibits a core-shell structure comprising at least one silsesquioxane core and at least two polymer chains chemically bonded to each of the silsesquioxane cores, the shell comprising at least two polymer chains; At least two polymer chains emanate from the silsesquioxane core to form a hyperbranched polymer, such that one end of each polymer chain is chemically bonded to the silsesquioxane core while allowing the other end to dangle freely. The hyperbranched polymers mentioned above are discrete molecules. The polymer chain described herein contains no olefinic unsaturation along its main chain. The polymer chains therein are not cross-linked.

16. The method of claim 15, wherein the step of providing the precursor comprises polymerizing (meth)acrylate monomers in the presence of a free radical initiator and a silane-containing chain transfer agent CTA, optionally wherein one or both of the following (A)-(B) are applicable: (A) The molar ratio of the CTA to the free radical initiator is 200:1 to 1:2; (B) The structure of the CTA is as follows: Where R is the organic linking group located between the thiol and the hydrolyzable silane moiety, X is the hydrolyzable group, Y is the organic functional group, and the value of "a" is 0. X is selected from the group consisting of the following: halogens, acyloxy groups, ketooxime ester groups, alkoxy groups, and combinations thereof.

17. The method of claim 16, wherein the free radical initiator is activated upon exposure to at least one of heat, photochemical radiation, and electron beam radiation.

18. The method of claim 15, wherein the hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur at a temperature range of 20°C to 50°C and 51°C to 170°C. Optionally, the hydrolysis reaction and the condensation reaction, or only the condensation reaction, occur in the presence of a catalyst. Furthermore, optionally, the amount of said catalyst is 0.5% to 5% by weight of the precursor.

19. The method of claim 15, further comprising: A core modifier is provided before and / or during the hydrolysis and condensation reaction of the precursor, or only the condensation reaction.

20. The method of claim 15, further comprising the step of adding a thickener. Optionally, the thickener is substantially compatible with the precursor.

21. The method of claim 15, further comprising the following steps: During the condensation reaction, a certain amount of polyol is added to connect each of the silsesquioxane cores of a portion of the hyperbranched polymer in series with and covalently link them to another silsesquioxane core to form a beaded structure, wherein the polyol has the following structure: Where R is a spacer group located between OH groups, and n is selected from the following groups: 2, 3, 4 and their combinations.

22. The method of claim 15, further comprising the following steps: During the condensation reaction, a certain amount of hydrolyzable disilane is added to connect each of the silsesquioxane cores of a portion of the hyperbranched polymer with one or more other silsesquioxane cores to form a multidimensional network structure, wherein the hydrolyzable disilane has the following structure: Wherein R is an organic group located between two hydrolyzable silane moieties, X is a hydrolyzable group, Y is an organic functional group, and each "a" is independently selected from 0, 1, and 2, optionally wherein any one or more of the following (A)-(C) are applicable: (A) The multidimensional network is a two-dimensional structure. (B) The amount of the hydrolyzable disilane is from 0% by weight to 30% by weight and not 0% by weight of the pressure-sensitive adhesive. (c)X is selected from the group consisting of: halogens, acyloxy groups, ketooxime ester groups, alkoxy groups and combinations thereof.

23. The method of claim 15, wherein the polymer chain contains no olefinic unsaturation along the main chain of the polymer chain.

24. The method of claim 15, wherein any one of the following (A)-(Q) applies: (A) The silsesquioxane core is selected from the group consisting of: pure silsesquioxane cores, hybrid silsesquioxane cores and combinations thereof, and optionally the silsesquioxane core is selected from the group consisting of: fully condensed cores, partially condensed cores and combinations thereof. (B) The method further includes: A core modifier is provided before and / or during the hydrolysis and condensation reaction, or only the condensation reaction, of the precursor, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core are replaced by atoms M of the core modifier, the core modifier having a molecular formula selected from the group consisting of: MX, MX2, MX3, MX4, MX5, MX6, RMX, RMX2, RMX3, RMX4, RMX5, and RMX6, wherein R is selected from the group consisting of: alkyl, alkenyl, aryl, H, and combinations thereof, M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, and X is selected from the group consisting of: organic monodentate ligands, organic bidentate ligands, organic tridentate ligands, and combinations thereof; (C) The method further comprises: providing a core modifier before and / or during the hydrolysis and condensation reaction, or only the condensation reaction, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by atoms M of the core modifier, the core modifier having a molecular formula selected from the group consisting of: M(X)4 and M(X). a (Z) b M is independently selected from Al, Si, Ge, Sn, Ti, and Zr, a is 2, b is 2, X is a hydrolyzable group, and Z is a compound of formula AC(O)-(R'). n -C(O)-B organic ligands, where R' is an organic group, n is an integer from 0 to 10, A is an organic group, and B is an organic group; (D) The method further comprises: providing a core modifier before and / or during the hydrolysis and condensation reaction, or only the condensation reaction, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core being replaced by another Si atom of the core modifier, the core modifier having the formula R". 4-q Si(OR#) q , where R" is a functional or nonfunctional hydrocarbon group, R# is selected from the group consisting of: methyl, ethyl and isopropyl, and q is 2 or 3; (E) The method further comprises: providing a core modifier before and / or during the hydrolysis and condensation reaction of the precursor, or only the condensation reaction, wherein the silsesquioxane core comprises a hybrid core, one or more Si atoms in the hybrid core are replaced by another Si atom of the core modifier, the core modifier having the formula Si(OR#)4, wherein R# is selected from the group consisting of methyl, ethyl and isopropyl; (F) The polymer chain comprises a polymer formed by linking (meth)acrylate monomers, the polymer being selected from the group consisting of: linear homopolymers, branched homopolymers, linear copolymers, branched copolymers, and combinations thereof; (G) The polymer chain is composed of (meth)acrylate polymer chains; (H) The pressure-sensitive adhesive contains at least 50% by weight of (meth)acrylate monomer; (I) The method further includes the step of adding an oligomer having at least one crosslinkable functional group. Optionally, the oligomer is a liquid at room temperature, and Optionally, the oligomer has a backbone selected from the group consisting of: polyethers, amorphous polyalphaolefins, polybutadiene, polyisoprene, polydimethylsiloxane, polyalkyloxazoline, polyesters, poly(meth)acrylates, polyurethanes, and combinations thereof. (J) The fully condensed silsesquioxane core has the general formula [RSiO 3 / 2 ] n , where n is an even number and R is a polymer chain; (K) The partially condensed silsesquioxane core has the general formula [R-SiO] 3 / 2 ] n (H2O) (3n / 2)-x , where "n" is a positive integer, "x" is a positive integer value less than 3n / 2, and R is a polymer chain; (L) The silsesquioxane core is at least one of cage-like, polymeric, ladder-like, or combinations thereof; (M) The number-average molecular weight Mn of the precursor, as determined by gel permeation chromatography, is from 59,495 to 300,000 g / mol. (N) The number-average molecular weight Mn of the precursor was determined by gel permeation chromatography to be in the range of 30,078 to 88,024 g / mol; (O) The number-average molecular weight Mn of the pressure-sensitive adhesive is in the range of 20,000 to 1,000,000 g / mol, as determined by gel permeation chromatography. (P) The pressure-sensitive adhesive exhibits a glass transition temperature Tg of 10°C to -60°C as determined by differential scanning calorimetry (DSC); or (Q) The pressure-sensitive adhesive exhibits a dynamic mechanical strength of 5 × 10⁻⁶ at 25°C and 1 radians / second, as determined by DMA. 4 -6×10 6 dynes / cm 2 The platform shear modulus.

25. The method of claim 24, wherein X in (B) is an organic amphipathic ligand.

26. The method of claim 24, wherein the organic monodentate ligand in (B) is a halogen.

27. The method of claim 24, wherein X in (B) is an alkoxide.

28. The method according to claim 24, wherein the amorphous poly-α-olefin in (I) is polyisobutylene.

29. The method according to claim 24, wherein R in (J) is a (meth)acrylate polymer chain.

30. The method of claim 24, wherein R in (K) is a (meth)acrylate polymer chain.

31. An article comprising the pressure-sensitive adhesive according to claim 1 or the pressure-sensitive adhesive formed by the method according to claim 15, wherein the article further comprises: Substrate with defined surfaces; The pressure-sensitive adhesive is disposed on at least a portion of the surface of the substrate.

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