WO2022141224A1

WO2022141224A1 - Cured silicone adhesive composition

Info

Publication number: WO2022141224A1
Application number: PCT/CN2020/141515
Authority: WO
Inventors: Chao Yang; Christopher B. Walker
Original assignee: 3M Innovative Properties Company
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-07
Also published as: TW202237792A

Abstract

The present invention provides a cured silicone adhesive composition, the cured silicone adhesive composition comprises an effective amount of a tackifier and a reaction product of the following reaction components: an optional vinyl functional siloxane having a vinyl functionality of two or more and diphenylsiloxane units; a siloxane gum compnsing diphenyl siloxane groups and vinylalkyl siloxane groups; a silicone hydride functional crosslinker having at least two Si-H groups; and an effective amount of a precious metal catalyst; wherein the molar ratio of Si-H to vinyl in the cured silicone adhesive composition is from 1.4 to 4.5, the total weight percentage of diphenylsiloxane units is 6%to 11%, based on the total weight of the cured silicone adhesive composition, and the cured silicone adhesive composition has a tan delta of at least 0.27 in a range of temperature from 25℃ to 200℃. Dampmg films comprismg the cured silicone adhesive composition are provided. Microspeaker diaphragm materials comprising sueh damping films are also provided.

Description

CURED SILICONE ADHESIVE COMPOSITION

TECHNICAL FIELD

This disclosure relates to the technical field of cured adhesives, and particularly, to cured silicone adhesive for use as damping adhesive layer in sheet materials, such as may be converted into microspeaker diaphragms.

BACKGROUND

Microspeakers are increasingly common in small electronics such as cell phones, tablets, earbuds, headphones and laptop computers. Microspeaker diaphragms are ideally light weight and very rigid, so as to exhibit pure pistonic motion, and also well damped, to suppress undriven motion or resonances that result in distorted reproduction of sound. In some cases, diaphragm materials are multi-layer membranes comprising at least a damping layer.

The damping layer may also function as an adhesive binding other layers together. The majority of microspeaker diaphragm damping adhesives are employed in 3 layer laminate constructions in which the adhesive is deployed between 2 layers of PEEK, an expensive thermoplastic with Tg of ～143℃. As the PEEK is typically very thin (5-9 microns) , it is challenging to handle it as a web in a traditional coating line. It is even more difficult to cure an adhesive at elevated temperatures on PEEK if the temperatures approach or surpass the Tg of PEEK.

As peroxide cure of silicones with benozyl peroxide requires temperatures of 150℃ or higher, coating and curing it on PEEK is excessively challenging as the PEEK shrinks in the curing ovens, changing the dimensions of the coated adhesive. Consequently, constructing PEEK laminates with peroxide cured silicones require coating the adhesive on an expensive fluorosilicone treated liner, which must be subsequently removed and the PEEK film laminated to the adhesive. If 2 liners are used, the process must be repeated twice. Liner removal and PEEK lamination adds production steps, lowers yield, and increases cost relative to coating directly on PEEK.

It would be desirable to have a silicone adhesive that could provide the properties of high temperature damping at key microspeaker frequencies while maintaining high shear performance at elevated temperatures. And the cured silicone adhesive has low Tg (i.e., lower than 0 ℃) without the use of high temperatures (i.e., greater than 150 ℃) curing.

SUMMARY

In view of the technical problems above, an object of the present disclosure is to provide a cured silicone adhesive composition, comprising an effective amount of a tackifier and reaction products of the following reaction components: an optional vinyl functional siloxane having a vinyl functionality of two or more and diphenylsiloxane units; a siloxane gum comprising diphenyl siloxane groups and vinylalkyl siloxane groups; a silicone hydride functional crosslinker having at least two Si-H groups; and an effective amount of a precious metal catalyst; wherein the molar ratio of Si-H to vinyl in the cured silicone adhesive composition is from 1.4 to 4.5, and the total weight percentage of diphenylsiloxane units is 6%to 11%, according to the formula -Si (Ph) ₂-O-, based on the total weight of the cured silicone adhesive composition, and the cured silicone adhesive composition has a tan delta of at least 0.27 in a range of temperature from 25℃ to 200℃.

In another aspect, the present disclosure provides a damping film comprising a cured silicone adhesive composition according to the present disclosure.

In another aspect, the present disclosure provides microspeaker diaphragm comprising a damping layer, wherein the damping layer is a damping film according to the present disclosure.

In some embodiments of the diaphragms of the present disclosure, the diaphragm comprises two or more stiff layers and at least one damping layer, where the damping layer is a damping film according to the present disclosure.

Additional embodiments of the microspeaker diaphragm materials of the present disclosure are descrived below under “Selected Embodiments. ”

Compared with the prior art, the present invention has the following beneficial effects:

1) The silicone adhesive damping material has high temperature damping performance while maintaining high temperature shear performance.

2) The silicone adhesive can be cured at temperature lower than 146℃, and it can be easily coated and cured directly on stiff layer to form a limination structure.

3) The raw materials of silicone adhesive can react well with each other to give a good PSA.

The preceding summary of the present disclosure is not intended to describe each embodiment of the present invention. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects and advantages of the invention will be apparent from the description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying figures, in which:

FIG. 1 is a graph presenting dynamic mechanical analysis data measured for one embodiment (that is, Example 5) of the present disclosure; and

FIG. 2 is a master rheological curve of Example 5.

DETAILED DESCRIPTION AND ILLUSTRATIVE EMBODIMENTS

The present invention will be further described in detail below in conjunction with the embodiments. It will be appreciated that other embodiments are considered, and can be practiced without departing from the scope and spirit of the present invention. Therefore, the following detailed description is non-limiting.

Unless otherwise specified, all numbers used in this Description and the Claims representing the characteristic sizes and quantities and physical properties should be understood as being modified by the term “approximately” under any and all circumstances. Therefore, unless stated on the contrary, parameters in numerical values listed in the above description and in the attached claims are all approximate values, and those of skill in the art are capable of seeking to obtain desired properties by taking advantage of contents of the teachings disclosed herein, and changing these approximate values appropriately. The use of a numeric value range represented by endpoints includes all numbers within such range and any range within such range, e.g., 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5 etc.

In this application:

As used in this speficication and the appended claims, the singular forms “a” , “an” , and “the” encompass emobodiments having plural referents, unless the content clearly dicates otherwise.

As used herein, “have” , “having” , “include” , “including” , “comprise” , “comprising” or the like are used in their open ended sense, and generally mean “including, but not limited to” . It will be understood that the terms “consisting of” and “consisting essentially of” are subsumed in the term “comprising” , and the like.

As used herein, the terms “cure” and “curable” refer to joining polymer chains together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network polymer. Therefore, in this disclosure the terms “cured” and “crosslinked” may be used interchangeably. A cured or crosslinked polymer is generally characterized by insolubility, but it may be swellable in the presence of an appropriate solvent. Polymers that are not crosslinked will soften and flow at high temperatures, where as those that are crosslinked will not flow at higher temperatures.

As used herein, polysiloxanes are polymers comprising repeating repeating Si -O -units in which the number of repeating units may be tens to hundreds to millions of repeat units. As silicon is tetravalent, the polysiloxanes also include substituents on the silicone atom. These substituents may be the same or different and often include aliphatic or aromatic groups bonded to the silicon atom. The polysiloxane may include copolymers in which some of the repeats units are - (R ₁R ₂ Si-O) -other units are - (R ₃R ₄ Si-O) -and other units are - (R ₅R ₆ Si-O) -where the R groups are hydrogen, aliphatic, alkenyl, or aromatic groups. In many cases the polysiloxanes are terminated with R ₇Si-O groups. If there are different types of repeat units present, the polysiloxane is considered a copolymer.

As used herein, the terms “siloxane” and “silicone” are interchangeable.

As used herein, “hydrogen” as a substituent refers to hydrogen atoms covalently bonded to silicon atoms in the polysiloxane chain. Polysiloxanes in which silicon atoms are bonded to hydrogen are referred to as silicon hydride groups and are useful for precious metal catalyzed crosslinnking reactions with other polymers in which alkenyl groups are present.

As used herein, the term “aliphatic” refers to C1-C40, suitably C1-C30, straight or branched chain alkenyl, alkyl, or alkynyl which may or may not be interrupted or substituted by one or more heteroatoms such as O, N, or S.

As used herein, the term “aromatic” refers to C3-C40, suitably C3-C30, aromatic groups including both carbocyclic aromatic groups as well as heterocyclic aromatic groups containing one or more of the heteroatoms, O, N, or S, and fused ring systems containing one or more of these aromatic groups fused together.

As used herein, the term “alkyl” refers to a monovalent group that is a radical of an alkane and includes straight-chain, branched, cyclic, and bicyclic alkyl groups, and combinations thereof, including substituted alkyl groups. Unless otherwise indicated, the alkyl groups typically contain from 1 to 30 carbon atoms. In some embodiments, the alkyl groups contain 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, or 1 to 3 carbon atoms. Examples of “alkyl” groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, isobutyl, t-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, and the like.

As used herein, the term “vinylalkyl silicone group” refers to a group with a silicon atom in the middle of the polysiloxane chain having one vinyl group and one alkyl group and 2 oxygen atoms in turn bonded to two more silicon atoms, e.g. Si -O -Si -O -Si, with the vinyl alkyl substituted silicone as the midlle of this group and the repeating Si-O units create a polysilooxane chain hundreds if not thousand or tens of thousand units long.

As used herein, the term “alkenyl” refers to a group which is characterized by the presence of a carbon carbon double bond, also referred to as unsaturated carbons. Vinyl groups are a very significant type of alkenyl group that participates in a platinum catalyzed addition reaction between a polymer with a silicone hydride group “Si-H” and a polymer with a vinyl group so as to create a “Si-CH ₂-CH ₂-Si” crosslink between the two polymer chains. The carbon carbon double bond may be directly attached to the silicon atom or there may be saturated carbon atoms (e.g. -CH ₂-CH ₂-groups between the silicone atom and the alkenyl group. If the carbon-carbon double bond consists of a -CH=CH ₂ group directly bonded to the silicon atom (e.g. Si-CH=CH ₂) , this also referred to as a vinyl group. Unless otherwise indicated, the alkylene group typically has 1 to 30 carbon atoms. In some embodiments, the alkylene group has 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms.

As used herein, the term “aryl” refers to a monovalent group that is aromatic and, optionally, carbocyclic. The aryl has at least one aromatic ring. Any additional rings can be unsaturated, partially saturated, saturated, or aromatic. Optionally, the aromatic ring can have one or more additional carbocyclic rings that are fused to the aromatic ring. Unless otherwise indicated, the aryl groups typically contain from 6 to 30 carbon atoms. In some embodiments, the aryl groups contain 6 to 20, 6 to 18, 6 to 16, 6 to 12, or 6 to 10 carbon atoms. Examples of an aryl group include phenyl, naphthyl, biphenyl, phenanthryl, and anthracyl.

The present invention provides a cured pressure sensitive silicone adhesive. According to the technical solution of the present invention, a cured silicone adhesive composition, comprising an effective amount of a tackifier and a reaction products of the following reaction components: an optional vinyl functional siloxane having a vinyl functionality of two or more and diphenylsiloxane units; a siloxane gum comprising diphenyl siloxane groups and vinylalkyl siloxane groups; a silicone hydride functional crosslinker having at least two Si-H groups; and an effective amount of a precious metal catalyst; wherein the molar ratio of Si-H to vinyl in the cured silicone adhesive composition is from 1.4 to 4.5, and the total weight percentage of diphenylsiloxane units is 6%to 11%, according to the formula -Si (Ph) ₂-O-, based on the total weight of the cured silicone adhesive composition, and the cured silicone adhesive composition has a tan delta of at least 0.27 in a range of temperature from 25 ℃ to 200℃.

Vinyl functional silicones

Typically, the vinyl functional silicones, suitable for present disclosure, contain two or more vinyl groups per polymer chain and typically the silicone hydride functional crosslinkers contain two or more Si-H functional groups per chain. When the number of either functional groups is equal to or greater than 2, the system crosslinks -what were previously different polymer chains are now covalently attached. With sufficient crosslinking, all of the polymer chains are connected. Extremely high molecular weights are achieved and adhesive properties such as high temperature shear performance are greatly enhanced.

Preferably, the vinyl functional silicones have a functionality (Vinyl group) of two or more. The method for determining the functionality comprises: determining the number average molecular weight (Mn) by using gel permeation chromatography (GPC) , and calculating the functionality by combining the Mn determined by GPC and the total number of functional groups determined by nuclear magnetic resonance spectroscopy (NMR) . When the functionality of the vinyl functional silicone is in the above range, the reactivity of the vinyl functional silicones can be controlled.

When the vinyl functional silicone having a functionality of less than 2 is used, an insufficient crosslinked network leads to poor high temperature resistance.

Moreover, the amount of the vinyl functional silicones in the cured silicone adhesive composition is from as at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, or at least 40 wt%and up to 70 wt%, up to 65 wt%, up to 60 wt%, up to 55 wt%, or up to 50 wt%. In some embodiments, the amount of the vinyl functional silicones is in a range of 30 to 70 wt%, and preferably from 20 to 60 wt%.

According to some embodiments of the present invention, the cured silicone adhesive compositions comprise a vinyl functional silicone have diphenylsiloxane units as an essential component. Without diphenylsiloxane units, the vinyl functional silicone can’t react well with the silicone gum to make a good PSA, e.g. blends of vinyl terminated polydimethylsiloxane (155,000 molecular weight) , vinyl-alkyl-diphenyl gums and MQ tackifier are often immiscible in proportions needed to get to a Tg of -20 to -30℃.

In some embodiments, the vinyl functional silicones have diphenylsiloxane units. The diphenylsiloxane units could be provided by another source, such as siloxane gum. That is, an appropriate amount of diphenylsiloxane units in both silicone gum and vinyl functional silicone is preferred.

The diphenylsiloxane units may be present in the cured silicone adhesive composition, in a formula -Si (Ph) ₂-O-, in a total amount of between 6 wt. %and 11 wt. %, or between 6 wt. %and 10 wt. %, based on the total weight of the cured composition.

In some preferred embodiments, the vinyl functional silicones include dimethyl siloxane-co-diphenyl siloxane-co-vinylmethyl siloxane. The dimethyl siloxane-co-diphenyl siloxane-co-vinylmethyl siloxane has 10.0 -16.0 mass percentages of diphenyl groups, 75-90 mass percentages of dimethyl groups, 0.02 -0.25 mass percentages of vinylmethyl groups and vinyl equivalent weights of 30, 000 -100, 000 g/eq. Examples of vinyl functional siloxanes includes VGP-061, available from Gelest:

In some preferred embodiments, the vinyl functional silicones include vinyl terminated polydimethylsiloxane-co-diphenyl siloxane. Example of vinyl functional siloxanes includes divinyl terminated polydimethylsiloxane-co-diphenyl siloxane with 10-40 mass percentages of diphenyl groups, 60-90 mass percentages of dimethyl groups and vinyl equivalent weights of 3, 000-25, 000 g/eq. Examples of vinyl functional siloxanes includes PDV0541 available from Gelest, and CAS 68951-96-2 (e.g. Gelest PDV-1631) shown below:

It may be possible to add a small amount (e.g. less than 10 wt. %) of the vinyl terminated polydimethylsiloxane to above mentioned vinyl functional siloxane with diphenyl-co-dimethyl group and still be miscible. Examples of vinyl terminated siloxanes are those sold by Gelest, Inc of Morrisville, PA and have vinyl groups on the end of the chain (e.g. Gelest DMS-V42 CAS 68083-19-2) as shown here:

Vinyl functionality may also be located on the interior of polysiloxanes. It may be possible to add this type of polysiloxanes to the vinyl functional siloxane with diphenyl-co-dimethyl group and still be miscible. An example is the structure as shown below representing CAS 67762-94-1 (e.g. Gelest VDT-163) :

Silicone gum

Silicone gums of this disclosure are vinyl functional silicone gum having vinyl functionality of 2. In some preferred embodiments, the vinyl functional silicone gums comprise diphenyl siloxane groups, and vinyl alkyl siloxane groups; wherein the vinyl functionality is located on the gum and is not on the tackifier. Silicone gums includes dimethyl-co diphenyl-co vinyl alkyl gum, and the vinyl groups are not on the end of the gum.

In some embodiments, a suitable silicone gum comprises diphenyl siloxane groups (D _Ph2) , dimethyl siloxane groups (D ₂) and vinylmethyl siloxane groups (D _vi) , with the following mass percentages ranges: D _Ph2 of 11-17; D ₂ of 82-89; D _vi of 0.03-0.09 and vinyl equivalent weight of 100, 000 to 200, 000 g/eq. An example is the gum present as part of the adhesive sold by Shin Etsu as KCT009AC, the other part of the adhesive is the MQ tackifier.

In some embodiment, a suitable silicone gum comprises vinyl methyl siloxane-co-dimethyl siloxane-co-diphenyl siloxane, which has 11-17 mass percentages of diphenyl siloxane groups, 82-89 mass percentages of dimethyl siloxane groups, 0.03-0.09 mass percentages of vinylmethyl siloxane groups and vinyl equivalent weights of 100, 000 to 200, 000.

In some embodiments, a suitable silicone gum comprises diphenyl siloxane groups (D _Ph2) , dimethyl siloxane groups (D ₂) and vinylmethyl siloxane groups (D _vi) , with the following mass percentages ranges: D _Ph2 of 11-17; D ₂ of 82-89; D _vi of 0.02-2.0 and vinyl equivalent weight of 50, 000 to 200, 000 g/eq. An example is the gum present as part of the adhesive sold by Shin Etsu as KCT009AC, the other part of the adhesive is the MQ tackifier.

In some embodiments, an examples of silicone gum includes VGP-061, available from Gelest.

Silicone hydride functional crosslinker

Silicone hydride functional crosslinkers include those with two or more Si-H functional groups such as the commnly used homopolymer of CAS 63148-57-2, (Gelest HMS-993) or from Shin-Etsu as X92-122C as generically shown below:

In some embodiments, a commonly used silicone hybride functional crosslinker includes trimethylsiloxyterminated polymethylhydrosiloxane, available from Shin-Etsu as X92-122C.

In some embodiments, a commonly used coplymer of CAS 68037-59-2 (Gelest HMS-151) shown below:

In some embodiments, a phenyl substituted silicone hydride crosslinker, CAS 925454-54-2 (Gelest HDP-111) shown below:

In some embodiments, another suitable Silicone hydride functional crosslinker, HPM-502 (Gelest, 115487-49-5) shown below:

It is found that the level of silicon hydride crosslinker dramatically affected the damping and the high temperature shear properties. an insufficient crosslinked network leads to poor high temperature resistance. When the crosslinking is too low, the high tempeature stability is inadequate as shown by poor high temperature shears. When it is over-crosslinked, the system has insufficient damping at higher temperatures.

Precious metal catalyst

Precious metal catalysts may be used in embodiments of the present disclosure include those suitable for catalyzing addition cure reaction of polymers with alkenyl groups (primarily vinyl) with silicone hydride functional crosslinkers to covalently connect and crosslink different polymer chains. In some embodiments, suitable catalyst including precious metal catalyst, such as platinum complexes or rhodium complexes may be used. In some embodiments, useful platinum complexes for catalyzing addition cure include those from Gelest, such as the series SIP 6829, SIP 6831, and 6832, as well as those sold by Dow (Syloff 4000) , CAT-PL-50T (from Shin Etsu) and others. Pt based catalysts are frequently complexes of vinyl species with Pt. The molar ratio of Si-H to vinyl (index) in the cured silicone adhesive need to take the vinyl ligands on the Pt catalyst into consideration. Upon heating the Pt is activated. Other Pt based catalysts include those that are photochemcially activated (e, g, PtCpMe ₃ or Pt (AcAc) ₂) .

Tackifiers

In some embodiments, the cured silicone adhesive compositions of the present disclosure may optionally include one or more tackifiers.

The tackifiers for cured silicone adhesive compositions are invariably MQ resins. These materials possess “Q” groups with Si bonded to 4 oxygen atoms and “M” groups with Si bonded to 1 oxygen atom and 3 carbon atoms. The 3 carbons are usually methyl groups. Q4 groups are silicone atoms bonded to 4 oxygen atoms and each of the 4 oxygen atoms is in turn attached to another silicon atom. Q3 groups are silicone atoms bonded to 4 oxygen atoms and 3 of the oxygen atoms are bonded to another silicone atom. Typically, the 4th oxygen atom is bonded to a hydrogen atom. There are M and Q groups in all silicone adhesive tackifiers of disclosure. MQ resins are available from Dow (Dowsil 2-7066) and Momentive (SR 545) . Siltech offers MQ resin where some of the “M” groups are replaced with vinyl functionality, e.g. (CH ₂=CH) Si (CH ₃) ₂ -O -under the brand Silmer; two examples are Silmer VQ20 and VQXYL. SiVance offers 100%solids MQ as MQOH7. Moreover, the amount of the tackifiers in the cured silicone adhesive composition is from as at least 30 wt%, at least 35 wt%, at least 45 wt%, and up to 70 wt%, up to 65 wt%, up to 60 wt%, up to 55 wt%, or up to 50 wt%. In some embodiments, the amount of the tackifier is in a range of 30 to 70 wt%, and preferably from 40 to 60 wt%.

Cured silicone adhesive

In some embodiments, the cured silicone adhesive compositions, may have a glass transition temperature that ranges from -12℃ to -31℃.

When the glass transition temperature of cured silicone adhesive composition is too high (i.e. greater than-12℃ in 1 Hz rheology) , the frequency of maximum damping in a 25℃ master curve is too low (＜100 Hz) . The glass transition temperature range of the cured silicone adhesive composition needs to meet the requirements (i.e., in the range of from -14 ℃ to -31℃) . In some embodiments, cured silicone adhesive composition having a glass transition temperature of at least -12 ℃, at least -14 ℃, and at least -16 ℃. This demonstrates that when the cured silicone adhesive composition has a glass transition temperature ranging from -12 ℃ to -31 ℃, the adhesive film has a good overall performance in terms of maximizing damping of frequencies of interest (typically 100-1000 Hz) in the handheld device microspeakers.

In some embodiment, the cured silicone adhesive compositions have a molar ratio of Si-H to vinyl being from 1.4 to 4.5. In some preferred embodiment, the cured silicone adhesive compositions have a molar ratio of Si-H to vinyl being from 2 to 3. When the molar ratio of equivalents of silicone hydride to equivalents of vinyl is too low (i.e., lower than 1.2) the high temperature stability is inadequate as shown by poor 70℃ shears and predicted by tan delta (at 200℃) of ＞0.6. When the molar ratio of silicone hydride to vinyl is too high (i.e., greater than 3.0) , the system is over-crosslinked and has insufficient damping at higher temperatures.

The method for determining the molar ratio of Si-H to vinyl is described below.

¹H work is done on a Bruker Avance III 500 MHz NMR spectrometer. ²⁹Si work is done on a JEOL ECZ600R 600 MHz NMR spectrometer. Portions of the submitted samples were analyzed as solutions of unknown concentration in deuterated tetrahydrofuran (THF) . One dimensional (1D) proton can be collected in standard tubes in the standard way. One of the residual proto-solvent resonances was used as a secondary chemical shift reference in the proton dimension (δ=1.73 ppm) . All the NMR data were collected with the samples held at 25℃. In the absence of MQ resin, the amount of D _Ph2 can be determined from the proton spectrum, even in the presence of toluene. The integrals of the NMR signals are proportional to the number of moles of those protons. Dividing the integrals of different groups by the number of protons in resonance results in the number of moles of that moiety. By dividing the D _Ph2 integral by 10 and the D ₂ integral by 6 will result in the relative moles of D _Ph2 and D ₂. The presence of toluene does not obscure this quantification. The presence of MQ resins in the proton spectrum is insufficient for a full quantification. In this case, the sample is dissolved in deuterated THF and put into a 10mm FEP NMR tube to avoid background signal from the glass NMR tubes. The data is collected on a JEOL 600 MHz instrument on a Silicon free probe to avoid background signal. A recycle delay of 60 seconds is used to collect a ²⁹Si spectrum. In these cases, each moiety has only a single ²⁹Si, so integration of the different regions results in the direct molar ratio of the different groups. If a solvent is present, the two types of spectra ¹H and ²⁹Si are used together using one or more resonance as a cross-integration standard. The NMR analysis provides the composition of the polymers as well as the vinyl equivalent weight or silicon hydride equivalent weight of the polymers and solutions. The equivalent weights are used in the calculation of the molar ratio of silicone hydride (Si-H) to vinyl.

In some embodiments, the cured silicone adhesive compositions may have a tan delta of at least 0.27 between 25℃ and 200℃. In some embodiments, the cured silicone adhesive compositions may have a tan delta of at least 0.30 between 25℃ and 200℃. In some preferred embodiments, the cured silicone adhesive compositions may have a tan delta of at least 0.35 between 25℃ and 200℃.

In another aspect, the present disclosure provides a damping film comprising a cured silicone adhesive composition, according to any one of the previous embodiments.

In some embodiments, the damping film, may have a shear adhesion strength at 70℃ with 1000 grams Weight, on stainless steel, of 1, 000 minutes or more, or preferred 10, 000 minutes or more, or preferred of 20, 000 minutes or more.

In some embodiments, the damping film may have a tan delta of at least 0.27, or at least 0.30, or at least 0.35 between 25℃ and 200℃.

In another aspect, the present disclosure provides a diaphragm for a microspeaker comprises a damping film, wherein the damping film comprising at least a damping film according to any one of the previous embodiments.

In some embodiments, the diaphragm for a microspeaker having multilayer laminate constructions, and the damping film further comprising at least a stiff layer.

Any suitable stiff layers may be used in embodiments of the present disclosure. In some embodiments, stiff layers comprise high temperature engineering thermoplastics. In some embodiments, stiff layers comprise materials selected from the group consisting of: polyethylene terephthalate (PET) , polycarbonate (PC) , polybutylene terephthalate (PBT) , polyethylene naphthalate (PEN) , polyetheretherketone (PEEK) , polyetherketone (PEK) , polyetherimide (PEI) , polyimide (PI) , polyarylate (PAR) , polyphenylene sulfide (PPS) , polyphenylsulfone (PPSU) , polysulfone (PSU) , polyethersulfone (PES) , polyurethane (PU) , and liquid crystal polymer (LCP) .

In some embodiments, stiff layers comprise polyether ether ketone (PEEK) . In some preferred embodiments, stiff layers comprise two PEEK stiff layers. As the PEEK is typically very thin (5-9 micron) , it is challenging to handle as a web in a traditional coating line. It is even more difficult to cure an adhesive at elevated temperatures on PEEK if the temperatures approach or surpass the Tg of PEEK. As peroxide cure of silicones with benzoyl peroxide requires temperatures of 150℃ or higher, coating and curing on PEEK is excessively challenging as the PEEK shrinks in the curing ovens, changing the dimensions of the coated adhesive. The cured silicone adhesive composition of current disclosure is cured at temperature lower than 146℃, and it can be easily coated and cured directly on PEEK stiff layer to form a lamination structure.

Hereinafter, the present invention is described in detail by way of embodiments. It is to be understood that the description and embodiments are intended to be illustrating, rather than limiting the present invention. The scope of the present invention is defined by the appended claims.

Examples

Unless otherwise noted, all reagents were obtained or are available from Aldrich Chemical Co., Milwaukee, WI, or may be synthesized by known methods.

In the present invention, unless otherwise indicated, the used reagents are all commercially available and are used directly without further purification. Further, the “%” mentioned is “wt%” , and the “parts” mentioned are “parts by weight. ”

Test Methods

The various cured silicone adhesives prepared in the exampless and comparative examples are tested for the adhesion property (Shear Adhesion Strength at 70℃) and Dynamic Mechanical Analysis according to the specific methods listed below.

Shear Adhesion Strength at 70 ℃ with 1000 grams Weight

Shear adhesion strength at 70℃ was measured according to ASTM D3654/D 3654M-06: “Standard Test Methods for Shear Adhesion of Pressure Sensitive Tapes” (Reapproved 2011) with testing conducted at 70℃. The adhesive was laminated to primed 0.002 inch (51 micrometers) polyester film. Tape samples measuring 25.4 millimeters (1.0 inches) by 15.2 centimeters (6.0 inches) were cut. The tape samples were then applied to a stainless steel panel previously wiped clean with methyl ethyl ketone (MEK) , then acetone, then n-heptane using lint free tissues. The samples were then centered on the panels and adhered to one end such that tape overlapped the panel by 25.4 millimeters (1 inch) in the lengthwise direction. The tape sample was then rolled down twice in each direction using a 2 kilograms (4.4 pounds) rubber roller at 12 inches/minute. The free end of the tape was folded over and adhered to itself such that there was no exposed adhesive. This free end was folded over and around a hanging hook and stapled together to secure the hook in place. The resulting panel /tape /weight assembly was suspended vertically in a stand at an angle of 2 degrees to ensure a shear failure mode in a 70℃ chamber. After 10 minutes of temperature equilibration, a 1.0 kilogram (2.2 pounds) weight was attached to the hook and the time, in minutes, for the tape to fall from the panel was recorded. The test was terminated as qualified if failure had not occurred by 1, 000 minutes and the result recorded as “＞1, 000” . The test was terminated as good if failure had not occurred by 10, 000 minutes and the result recorded as “＞10, 000” . The test was terminated as excellent if failure had not occurred by 20, 000 minutes and the result recorded as “＞20, 000” . The average for the two samples was reported. Shear testing of samples was performed witin 1-3 days after the sample was prepared.

Shear Adhesion Strength at 70℃ with 1000 grams Weight after 5 day 120℃ aging

The Shear Adhesion Strength at 70℃ with 1000 grams Weight method was performed, but after the hanging hook was stapled in place, the shear samples were placed in a 120℃ oven for 5 days. After 5 days, the samples were cooled to room temperature and then placed in the 70℃ shear chamber, the weight was attached and the samples were shear tested until failure.

Glass Transition Temperature

The glass transition temperature of cured silicone adhesive compositions prepared in the following embodiments and comparative example is measured by the following method. The glass transition temperatures defined by the present invention are all based on rheological data, where the temperature corresponding to the maximum value of the loss factor is taken as the glass transition temperature.

The rheological curve properties of cured silicone adhesive compositions prepared in the following embodiments and comparative examples are measured respectively by the following method.

Dynamic Mechanical Analysis (DMA)

Dynamic mechanical analysis was used to measure the storage modulus and glass transition temperatures of adhesives. A rheometer (Model DHR-2 or ARES-M, TA Instruments, New Castle, DE) having parallel top and bottom plates, each having a diameter of 8 millimeters was used. An adhesive sample in the form of a circular disk having a diameter of 8 millimeters and a thickness of approximately 1 millimeter was transferred onto the bottom plate of the rheometer. For the DHR-2 rheometer, the procedure was as follows: the sample was mounted between the parallel plates, conditioned at -40℃ for 3 minutes, then under went a temperature oscillation ramp (at a rate of 3℃/minute, at a frequency of 1 Hertz, and an initial strain smplitude of 2%with autostrain enabled) from -40℃ to 50℃, then under went a temperature oscillation ramp (at a rate of 3℃/minute, at a frequency of 1 Hertz, and an initial strain smplitude of 5%strain from 50℃ to 200℃ or 250℃) before finally cooling to room temperature.

Select samples were tested while being heated from -40℃ to 250℃ all other parameters the same. Storage modulus (G’) and Loss Modulus (G”) data were collected over the entire temperature range and reported in Pascals. Tan delta was calculated as the ratio of (loss modulus/storage modulus) = (G”/G’) . The temperature at which the tan delta curve exhibited a local peak was reported as the glass transition temperature (Tg) in ℃. G’ and tan delta at various temperatures including the minimum tan delta are reported in the tables.

FIG. 1 is a graph presenting dynamic mechanical anlysis data measured for Example 5. Line A represents G’ and line B represents G”, both referencing the left-hand scale. Line C represents tan delta, referencing the right hand scale. In the temperature sweep rheology (1 Hz) of Example 5 shown below, the maximum of the loss tangent (or tan delta) was at -15.8 ℃, which is defined as the Tg. The height of the tan delta curve was 1.11 at Tg and this was defined as TDmax. The minimum of the tan delta curve over the range -40℃ to 200 ℃ was 0.42 and was defined as TDmin. The value of tan delta at 200℃ was 0.48 and was defined as TD200. In some cases, the minimum value of tan delta occurs at 200℃, in which case the TDmin and the TD200 have the same value. The value of the storage modulus at 25℃ was 4.5 E+04 Pa and is defined as G’25. The change in tan delta between the minimum value and the value at 200℃ was obtained by subtraction of the value TD200minus the value at TDmin which in this example was 0.48-0.42=0.06. Common rheometers and software, such as the TA Instruments DHR-2 rheometer and TRIOS software, are capable of establishing master curves for presure sensitive adhesives. Through time temperature superposition principles, temperature sweeps of an adhesive at a variety of frequencies can be used to calculate shift factors and ultimately generate a master curve at room temperature, which provides the rheology of the adhesive at 25℃ over a wide range of frequencies. As the loss factor curve (or tan delta) is key to the damping properties of the adhesive, the master curve (MC) provides a way to evaluate adehsives ability to dampen the frequencies of interest for microspeakers (typically 100-1000 Hz) . The frequency at which the tan delta curve has a maximum value is defined as the MCmax frequency and the height of the tan delta curve of the master curve tan delta curve at that frequency is defined as the MC TDmax. FIG. 2 is the master curve of example 5, it can be seen that the MC TDmax was 1.11 and the MC max freq was 236 Hz.

Materials

NMR Analysis of siloxanes, PSAs, crosslinkers, and catalyst for equivalent weight and composition

VGP-061, PDV-0541, and PDV-1631 as recevied from Gelest were analyzed for composition and equivalent weight.

VGP-061 was found to consist of a dimethylsiloxane-co-diphenylsiloxane-co-vinylmethyl siloxane in a molar ratio of 93.86: 5.99: 0.15 with terminal trimethylsilyl groups. The mass ratio is 0.155 mass%vinylmethyl, 13.99 mass%diphenyl, 85.85 mass%dimethyl and the vinyl groups are internal or pendant, not on the terminal groups of the siloxane. Vinyl methyl siloxane groups have a vinyl group and a methyl group on a silicon atom as is illustrated below at left. The vinyl equivalent weight was found to be 55297 g/equivalent.

PDV-0541 was found to be a copolymer of dimethyl-siloxane-codiphenyl siloxane with terminal vinyl dimthylsilyl groups, as illustrated below on the right. The molar ratio of dimethylsiloxane to diphenyl siloxane is 94.52: 5.48. The mass%of dimethylsiloxane to diphenyl siloxane is 86.6: 13.4. The vinyl equivalent weight was found to be 18400 g/equivalent.

PDV-1631 was also found to be a copolymer of dimethyl-siloxane-codiphenyl siloxane with terminal vinyl dimthylsilyl groups. The molar ratio of dimethylsiloxane to diphenyl siloxane is 82.74: 17.26. The mass%of dimethylsiloxane to diphenyl siloxane is 64.2: 35.8. The vinyl equivalent weight was found to be 5506 g/equivalent.

KCT-009-AC was received and analyzed for composition and for equivalent weight. The results are presented not including the solvent, to reflect the composition of the material used in the dried adhesives formulated as examples and comparative examples.

Lot#A analysis

The Lot A analysis found the composition to be 56.5%tackifier (from M, Q3 and Q4 groups) and 43.5%of a gum, consisting of a copolymer of methylvinyl siloxane-co-dimethyl siloxane-codiphenyl siloxane. Normalizing to 100, the molar ratio was 0.05: 94.58: 5.37 for vinylmethylsiloxane: dimethylsiloxane: diphenyl siloxane in the gum and the mass ratio is 0.05: 86.52: 13.43. As was found in the analysis of VGP-061, the vinyl groups are located at internal positions of the silicone gum, not at terminal positions. The tackifier was also absent of vinyl groups. The equivalent weight of the vinyl groups in the gum alone was 159502. The equivalent weight of the vinyl groups in the dried adhesive was 373, 706 g/equivalent.

Lot#B analysis

The Lot B analysis found the composition to be 55.1%tackifier (from M, Q3 and Q4 groups) and 44.9%of a gum, consisting of a copolymer of methylvinyl siloxane-co-dimethyl siloxane-co-diphenyl siloxane. Normalizing to 100, the molar ratio was 0.064: 93.77: 6.17 for vinylmethylsiloxane: dimethylsiloxane: diphenyl siloxane in the gum and the mass ratio was 0.07: 84.93: 15.00. As was found in the analysis of VGP-061, the vinyl groups were located at internal positions of the silicone gum, not at terminal positions. The tackifier was also absent of vinyl groups. The equivalent weight of the vinyl groups in the gum alone was 127467. The equivalent weight of the vinyl groups in the dried adhesive was 284049 g/equivalent.

X92-122C was found to be a polymer of methylhydrogen siloxane, terminated with trimethylsilyl groups. The Si-H equivalent weight was 63.3 g/equivalent.

Dehesive 948 was found to be a vinyl terminated polydimethylsiloxane with an equivalent weight of 202, 000.

CAT-PL-50T was found to be 98%toluene in Pt with bound and unbound vinyl groups. The vinyl equivalent of the solution as received including all vinyl groups was determined to be 6000.

Examples and Comparative Examples

Preparation of 1%X92-122-C Toluene Solution

A solution of 1%cross-linker X92-122-C in toluene was prepared by adding the following materials to MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 0.80g of X92-122-C as obtained from vendor. Toluene was added to this solution until the total weight was 80.01g. These were mixed at 3000 rpm for 1min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) .

A 1%solution of X92-122-C in Toluene was obtained. The solution was transferred into a 200g clear jar.

Preparation of 1.37%%X92-122-C Toluene Solution

A solution of 1.37%cross-linker X92-122-C in toluene was prepared by adding the following materials to 1 liter glass jar: 9.71g of X92-122-C as obtained from Shin-Etsu and 700.0 g. of toluene. The solution was rolled on a jar roller for 15 minutes until the homogenous solution was obtained.

Preparation of 1%7678 in Toluene Solution

A solution of 1%cross-linker 7678 in toluene was prepared by adding the following materials to MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 0.80g of 7678 as obtained from vendor. Toluene was added to this solution until the total weight was 80.01g. These were mixed at 3000 rpm for 1min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) .

A 1%solution of 7678 in Toluene was obtained. The solution was transferred into a 200g clear jar.

Preparation of 10%CAT-PL-50T Toluene Solution

A solution of 10%catalyst CAT-PL-50T in toluene was prepared by adding the following materials to MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 3.01g of CAT-PL-50 as obtained from vendor. Toluene was added to this solution until the total weight was 30.08g. These were mixed at 3000 rpm for 1min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) .

A 10%solution of CAT-PL-50 in Toluene was obtained. The solution was transferred into a 100g brown jar.

Preparation of 30%VGP-061 in toluene

150g of VGP-061 (as received) wasa added to a 1 liter clear glass jar. 350 g of toluene was added and the mixture was placed on a mechanical jar roller. The jar rotated on the roller, thoroughly mixing the contents over 5 days, at which time it was judged to be uniform, clear and homogeneous.

Example 1

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.81 g solution of ShinEtsu KCT-009-AC (lot#B 61.1%solids) , 2.62 g of PDV-1631, and 8.96 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 5.25 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.88 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1 min. A 42.7%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 4.2 minutes.

An adhesive transfer tape having an adhesive layer with a thickness of approximately 30 micrometers on a release liner was obtained.

Example 2

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.82 g solution of ShinEtsu KCT-009-AC (lot#A 60.4%solids) , 2.21 g of PDV-1631, and 8.01 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 5.0 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.8%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 6.3 minutes.

Example 3

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 18.01 g solution of ShinEtsu KCT-009-AC (lot#A 60.4%solids) , 1.62 g of PDV-1631, and 4.08 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.97g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.08g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.6%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 2.25 minutes.

Example 4

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 54.0 g solution of ShinEtsu KCT-009-AC (lot#A 60.4%solids) , 4.45 g of PDV-1631, and 13.3 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 11.95 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 3.27 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.8%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 2.25 minutes.

Example 5

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 18.02 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 1.48 g of PDV-1631, and 4.10 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.98 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the solution was mixed twice at 3000 rpm for 1 min. 1.09 g solution of 10%CAT-PL-50 was added to the mixing cup and the mixture was speed mixed twice at 3000 rpm for 1min. A 43.3%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 2 minutes.

Example 6

To a 1 gallon glass jar was added 1000.9g of KCT009AC (lot#A 61.1%solids) , 82.4 g PDV-1631, and 541.3 g of toluene. The jar was placed on a roller where the contents mixed by the rolling motion of the jar for 48 hours. To the jar was added 162 g of 1.37%X92-122C in toluene and the jar was replaced on the jar roller and mixed for 2 hours. To the jar was added 60.0 g of 10%CAT-PL-50T in toluene along with 200 g additional toluene and the jar was mixed on the roller for an additional 1 hour to yield a 34%solids solution. The homogenous solution was pumped with a 1.168 cc/rev Zenith pump through a knife coater at 45 rpm with a 110 micron gap at 5 fpm, 12 inches wide onto the release treated side of 13 inch wide release liner SF 88001, followed by passing the coated liner through an oven having four zones set at the following temperatures: 80°F, 330°F, 330°F, and 330°F, (27℃, 130℃, 130℃, and 130℃) to remove solvent from the adhesive. The time at 330°F was 4.2 minutes. A line speed of 5 feet/minute was employed for the coating/drying process. The adhesive surface of the resulting article was laminated to the the release side of a 13 inch wide 1R88001 fluorosilicone, using a nip roller. An adhesive transfer tape having an adhesive layer with a thickness of 30 micrometers between two different release liners was obtained.

Example 7

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.19 g solution of ShinEtsu KCT-009-AC (lot#A 61.1%solids) , 2.6 g of PDV-1631, and 7.01 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 6.96 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.6%solids solution was obtained.

Example 8

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.81 g solution of ShinEtsu KCT-009-AC (lot#A 60.4%solids) , 2.22 g of PDV-1631, and 8.0 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 6.6 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 41.4%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 6.3 minutes.

Example 9

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.82 g solution of ShinEtsu KCT-009-AC (lot#A 60.4%solids) , 2.22 g of PDV-1631, and 8.0 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 7.2 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 40.9%solids solution was obtained.

Example 10

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.8 g solution of ShinEtsu KCT-009-AC (lot#B 61.1%, solids) , 2.64 g of PDV-0541, and 11.25 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.2 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.95 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.3%solids solution was obtained.

Example 11

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.8 g solution of ShinEtsu KCT-009-AC (lot#B 61.1%, solids) , 2.6 g of PDV-0541, and 12.5 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.71 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.84 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 41.7%solids solution was obtained.

Example 1

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.82 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 2.44 g of PDV-0541, and 13 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.01 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 40.4%solids solution was obtained.

Example 13

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.8 g solution of ShinEtsu KCT-009-AC (lot#A, 61.1%solids) , 2.44 g of PDV-0541, and 11 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.02 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.6%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 4.0 minutes.

Example 14

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.81 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 2.43 g of PDV-0541, and 11.01 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.11 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.0%solids solution was obtained.

Example 15

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 36.01 g solution of ShinEtsu KCT-009-AC (lot#A, 61.1%solids) , 3.0 g of PDV-0541, and 11.0 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.92 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 2.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 44.8%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 4.2 minutes.

Example 16

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.79 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 2.44 g of PDV-0541, and 11.02 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.24 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 41.9%solids solution was obtained.

Example 17

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 15.87 g solution of ShinEtsu KCT-009-AC (lot#A, 68.5%solids) , 1.48 g of PDV-0541, and 6.14 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 1.99 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.99 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 46.7%solids solution was obtained.

Example 18

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 54.0 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 4.44 g of PDV-0541, and 18.42 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 5.99 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 3.27 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.1%solids solution was obtained.

Example 19

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 30.0 g solution of ShinEtsu KCT-009-AC (lot#A, 61.1%solids) , 2.05 g of PDV-0541, and 9.0 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.96 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 2.0g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 44.4%solids solution was obtained.

Example 20

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 13.0 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 0.54 g PDV-1631, 0.54 g of PDV-0541, and 3.7 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.21 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.72 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.2%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 2.0 minutes.

Example 21

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 15.87 g solution of ShinEtsu KCT-009-AC (lot#A, 68.5%solids) , 0.76 g PDV-1631, 0.74 g of PDV-0541, and 5.42 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.82 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.72 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 47.1%solids solution was obtained.

An adhesive transfer tape having an adhesive layer with a thickness of approximately 31 micrometers on a release liner was obtained.

Example 22

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 36 g solution of ShinEtsu KCT-009-AC (lot#B, 61.1%solids) , 13.33 g of 30%solids VGP-061 in toluene, and 5 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.24 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 2.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.7%solids solution was obtained.

An adhesive transfer tape having an adhesive layer with a thickness of approximately 34 micrometers on a release liner was obtained.

Example 23

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 36 g solution of ShinEtsu KCT-009-AC (lot#B, 61.1%solids) , 13.33 g of 30%solids VGP-061 in toluene, and 5 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.6 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 2.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 44.2%solids solution was obtained.

Example 24

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 7.94 g of SR545 at 60%solids and 16.65 g of 30%VGP-061 (as silicone gum) in toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 1.9 g of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 35.5%solids solution was obtained.

An adhesive transfer tape having an adhesive layer with a thickness of approximately 25 micrometers on a release liner was obtained.

Comparative Example 1

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.79 g solution of ShinEtsu KCT-009-AC (lot#B, 61.1%solids) , 2.63 g of PDV-1631, and 9.45 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.14 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.99 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 45.0%solids solution was obtained.

Comparative Example 2

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.79 g solution of ShinEtsu KCT-009-AC (lot#B, 61.1%solids) , 2.63 g of PDV-1631, and 8.97 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 4.1 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.99 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 44.6%solids solution was obtained.

Comparative Example 3

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 27.94 g solution of ShinEtsu KCT-009-AC (lot#B, 62.5%solids) , 2.44 g of PDV-1631, and 6.01 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 8.81 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.5%solids solution was obtained.

Comparative Example 4

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 27.95 g solution of ShinEtsu KCT-009-AC (lot#B, 62.5%solids) , 2.45 g of PDV-1631, and 4.0 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 9.54 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.9 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.7%solids solution was obtained.

Comparative Example 5

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 17.47 g solution of ShinEtsu KCT-009-AC (lot#B, 62.5%solids) and 1.51 g of PDV-1631. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 7.11 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.11g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 45.9%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 135℃ (275°F) for 4.2 minutes.

Comparative Example 6

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 17.46 g solution of ShinEtsu KCT-009-AC (lot#B 62.5%solids) , 1.49 g of PDV-0541, and 5.7 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.65 g solution of 1%X92-122-C in toluene was added to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.99 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.9%solids solution was obtained.

Comparative Example 7

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 17.47 g solution of ShinEtsu KCT-009-AC (lot#B, 62.5%solids) , 1.49 g of PDV-0541, and 4.27 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.05 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.1 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 45.4%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.004 inches (101.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 135℃ (275°F) for 2 minutes.

Comparative Example 8

A coating solution was prepared by adding the following materials to a MAX 40 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 18.0 g solution of ShinEtsu KCT-009-AC (lot#A, 60.4%solids) , 0.82 g of PDV-1631, 0.81 g PDV0541, and 4.11 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.97 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.08 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.6%solids solution was obtained.

Comparative Example 9

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 54.01 g solution of ShinEtsu KCT-009-AC (lot#B, 62.5%) , 16.93 g of a 30%solution of VGP-061 in toluene, and 16.01 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 7.2 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 3.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 45.6%solids solution was obtained.

Comparative Example 10

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 36.0 g solution of ShinEtsu KCT-009-AC (lot#B, 61.1%solids) , 13.33 g of a 30%solution of VGP-061 in toluene, and 5 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 3.81 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 2.0 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 43.3%solids solution was obtained.

Comparative Example 11

A coating solution was prepared by adding the following materials to a MAX 100 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 51.27 g solution of Dehesive 948, (19.5%solids) and 14.3 g of a 70%solution of 2-7066. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 1.46 g of a 1%solution of 7678 in toluene was added to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 0.18 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 29.8%solids solution was obtained.

The solution was coated on the release treated side of a fluorosilicone liner SF 88001, using a notchbar coater having a gap setting of 0.005 inches (126.6 μm) at a speed of 5 fpm. After 20-30 seconds of drying in air, the adhesive coated release liner was taped to a rectangular aluminum frame and the hand-spread was placed in oven at 130℃ (266°F) for 4.2 minutes.

Comparative Example 12

A coating solution was prepared by adding the following materials to a MAX 60 SPEEDMIXER cup (FlackTek, Incorporated, Landrum, SC) : 28.8 g solution of Dowasil 7956 (56%solids) , 2.64 g of PDV-1631, and 9.04 g of toluene. These were mixed at 3000 rpm for 1 min in a DAC 150.1 FVZ-K Speed-mixer (FlackTek Inc, Landrum, SC) . 2.63 g solution of 1%X92-122-C in toluene was aded to the mixing cup and then the mixture was mixed twice at 3000 rpm for 1min. 1.95 g solution of 10%CAT-PL-50 was added to the mixing cup and then the mixture was speed mixed twice at 3000 rpm for 1min. A 42.9%solids solution was obtained.

Silicone adhesive formulations were evaluated in rheology and 70℃ shears within a week of preparation. To assess rheology and shear performance after extended heat aging, samples of adhesive were also tested in rheology after 120℃ heat treatment for 5 days or shear sandwiches were tested in 70℃ testing after heat treatment of 5 days at 120℃.

In the following tables, “CE” means Comparative Example and “Ex” means Example. Table 1 represents the cured silicone adhesive composition content of the Examples and Comparative Examples. Percentages were weight percent based on total weight of cured silicone adhesive composition.

Caclculations of index (equivalents of Si-H groups divided by equivalents of vinyl groups) were done as follows:

1. Equivalents of Si-H were calculated by dividing the weight of dry crosslinker (e.g. X92-122C) by the equivalent weight of the dry crosslinker.

2. Equivalents of vinyl were calculated as follows: For each component that contains vinyl functionality, the calculated dry weight of that component that was used was divided by its equivalent weight providing the number of equivalents from that component. The sum of the equivalents from all vinyl components gives the total vinyl equivalents. For materials that contain no solvent (e.g. PDV-1631) , the weight of the component is the dry weight. For the vinyl functionality in the CAT-PL-50T, the equivalnt weight of 6000 refers to the CAT-PL-50T solution as received. For components that contain solvents, the weight of the solids are calculated and employed as the dry weight.

In the table below, the amount of dry crosslinker is provided as parts per hundred (phr) . For example if there was 0.26 g of dry crosslinker to 100 g of the sum total of all dried PSAs (including tackifier) and all vinyl containing species, the table would list 0.26 phr of crosslinker. In Table 1, the amount of Pt catalyst solids (including ligands) is presented as parts per million (ppm) . The ppm of Pt catalyst is not ppm of the metal itself, it is ppm of the solids in CAT-PL-50T, so it is the vinyl ligands and Pt. The weight of the Pt solids to the weight of the sum total of the all dried PSA (including tackifier) and all vinyl containing species is expressed as ppm.

Table 3. Test results of the cured silicone adhesives prepared in the Embodiments 1-2, 6-12, 14-16, 19-20, 22-23 and Comparative Examples 1-2 after 5 day 120℃ heat treatment.

Based on the results of Table 2, the high temperature shear performances were found to change with time. In Table 3, initial rheology parameters were found to change slowly with time. A five day 120℃ postbake was used to drive curing to completion and determine completed cure rheology.

CE11 is a comparative example without diphenyl silicone unit, an all methyl PSA is made by adding a vinyl terminated PDMS (Wacker 948) with an MQ (Dow 2-7066) and crosslinking with Dow 7678 Si-H and Pt (index 3.0) . This example has good shear result but the low high temperature damping performance.

CE12 is a comparative example comprising a siloxane gum without vinylalkyl siloxane groups. The high temperature damping is bad, and the shears are bad.

The embodiments of the present invention described above are merely illustrative of the preferred embodiments of the present invention, and are not intended to limit the concept and scope of the present invention. Various modifications and improvements can be made to the technical solution of the present invention by those skilled in the art without departing from the scope of the present invention, which are all embraced in the protection scope of the present invention as defined by appended claims.

Claims

A cured silicone adhesive composition, comprising an effective amount of a tackifier and a reaction product of the following reaction components:

an optional vinyl functional siloxane having a vinyl functionality of two or more and diphenylsiloxane units;

a siloxane gum comprising diphenyl siloxane groups and vinylalkyl siloxane groups;

a silicone hydride functional crosslinker having at least two Si-H groups; and

an effective amount of a precious metal catalyst;

wherein the molar ratio of Si-H to vinyl in the cured silicone adhesive composition is from 1.4 to 4.5, the total weight percentage of diphenylsiloxane units is 6%to 11%, based on the total weight of the cured silicone adhesive composition, and the cured silicone adhesive composition has a tan delta of at least 0.27 in a range of temperature from 25 ℃ to 200℃.
A cured silicone adhesive composition according to claim 1, wherein the molar ratio of Si-Hto vinyl is from 2 to 3.
A cured silicone adhesive composition according to claim 1, wherein the cured silicone adhesive composition has a tan delta of at least 0.35 in a range of temperature from 25 ℃ to 200℃.
A cured silicone adhesive composition according to claim 1, wherein the vinyl functional siloxane includes divinyl terminated polydimethylsiloxane-co-diphenyl siloxane with 10-40 mass percentages of diphenyl groups, 60-90 mass percentages of dimethyl groups and vinyl equivalent weights of 3,000-25,000 g/eq.
A cured silicone adhesive composition according to claim 1, wherein the vinyl functional siloxane includes dimethyl siloxane-co-diphenyl siloxane-co-vinylmethyl siloxane with 10.0 -16.0 mass percentages of diphenyl groups, 75-90 mass percentages of dimethyl groups , 0.02-0.25 mass percentages of vinylmethyl groups and vinyl equivalent weights of 30,000 -100,000 g/eq.
A cured silicone adhesive composition according to any one of claim 4 and 5, wherein the siloxane gum comprises 11-17 mass percentages of diphenyl siloxane groups, 82-89 mass percentages of dimethyl siloxane groups, 0.02-0.2 mass percentages of vinylmethyl siloxane groups and vinyl equivalent weights of 50,000 to 200,000.
A cured silicone adhesive composition according to claim 1, wherein the cured silicone adhesive composition, comprising an effective amount of a tackifier and a reaction product of the following reaction components:

a siloxane gum comprising diphenyl siloxane groups and vinylalkyl siloxane groups;

a silicone hydride functional crosslinker having at least two Si-H groups; and

an effective amount of a precious metal catalyst;

wherein the molar ratio of Si-H to vinyl in the cured silicone adhesive composition is from 1.4 to 4.5, the total weight percentages of diphenylsiloxane units is 6%to 11%, based on the total weight of the cured silicone adhesive composition, the silicone gum comprising 11-17 mass percentages of diphenyl siloxane groups, 82-89 mass percentages of dimethyl siloxane groups, 0.02-0.2 mass percentages of vinylmethyl siloxane groups and vinyl equivalent weights of 50,000 to 200,000, and the glass transition temperature of the cured silicon adhesive is -20℃ to -30℃.
A cured silicone adhesive composition according to claim 1, wherein the tackifier comprises a silicone tackifier comprising MQ resin.
A cured silicone adhesive composition according to claim 1, wherein the cured silicone adhesive composition has shear adhesion strength at 70℃ with 1000 grams Weight, on stainless steel, of 1,000 minutes or more.
A cured silicone adhesive composition according to claim 1, wherein the cured silicone adhesive composition has a tan delta of at most 0.9 for a temperature equal to 200℃.
A cured silicone adhesive composition according to claim 1, wherein the glass transition temperature of the cured silicone adhesive composition is -10℃ to -36℃.
A cured silicone adhesive composition according to claim 1, wherein the glass transition temperature of the cured silicone adhesive composition is -14℃ to -31 ℃.
A cured silicone adhesive composition according to claim 1, wherein the silicone hydride functional crosslinker includes trimethylsiloxyterminated polymethylhydrosiloxane.
A damping film used for microspeaker, wherein the damping film comprises a cured silicone adhesive composition according to any one of claim 1 to 13.
A damping film used for microspeaker according claim 14, wherein the thickness of the damping film is 5 to 50 micrometers.
A damping film used for microspeaker according claim 15, wherein the thickness of the damping film is 10 to 40 micrometers.
A diaphragm used for microspeaker having multilayer laminate construction, wherein the diaphragm comprises a damping film according to claim 14.
A diaphragm according to claim 17, wherein the diaphragm further comprising at least a stiff layer.
A diaphragm according to claim 18, wherein the stiff layer comprise a material whose principal constituent is selected from the group consisting of: polyethylene terephthalate (PET) , polycarbonate (PC) , polybutylene terephthalate (PBT) , polyethylene naphthalate (PEN) , polyetheretherketone (PEEK) , polyetherketone (PEK) , polyetherimide (PEI) , polyimide (PI) , polyarylate (PAR) , polyphenylene sulfide (PPS) , polyphenylsulfone (PPSU) , polysulfone (PSU) , polyethersulfone (PES) , polyurethane (PU) , and liquid crystal polymer (LCP) .